Oil & Gas Investment Symposium

1. Oil & Gas Investment Symposium AN INTEGRATED NATURAL GAS COMPANY Charles B. “Chuck” Stanley Executive Vice President and President & CEO, Questar Market Resources Sheraton New York Hotel & Towers New York City, NY April 21, 2004

2. Questar is an integrated natural gas company Assets: $3.3 billion December 2003 Regulated Services (Questar Pipeline and Questar Gas) Gas transmission, storage & distribution 50% of assets Market Resources (includes Wexpro) Gas & oil exploration, production, gathering, marketing and trading 50% of assets 29% of net income 67% of net income

3. We’re well positioned to capitalize on strong regional fundamentals WYOMING OVERTHRUST IDAHO GREEN RIVER NEVADA Salt Lake City SKULL CREEK SAND WASH UINTA PICEANCE FERRON Questar Gas PARADOX UTAH COLORADO SAN JUAN Questar Pipeline CALIFORNIA Other pipelines Principal producing basins ARIZONA NEW MEXICO Long Beach

4. Our strategies reflect our focus on returns, risk, and the Rockies • Improve returns on capital • Maintain a strong balance sheet • Grow reserves and production • Hedge production to manage price risk • Expand and extend our pipeline system • Capture value around key production areas

5. 2004 earnings guidance Key assumptions: • Hedges in place February 2004 • Forward-price curve applied to unhedged volumes $2.30 - $2.45 $2.06 $1.88 2004F 2003 2002

6. We focus on returns on capital Return on Assets 12 Months Ending December 2003 Questar Market Questar Questar Resources Pipeline Gas * Adjusted ROA is before FAS 143 and gas-processing charges and asset-sale gains

7. Hedging and cap-ex decisions reflect our view of long-term fundamentals • Hedge • Acquisition opportunities less likely Demand Destruction/Supply Response $3.75 per MMbtu Equilibrium Range $3.00 per MMbtu Base case economics NYMEX Supply Destruction/Demand Response Supply Destruction • Don’t hedge • Acquisition opportunities more likely Time

8. We pay a competitive dividend; our payout is conservative Dividends/Payout/Yield • Quarterly dividend $.205 per share • 30 increases in 31 years • $.82 annualized dividend • Current yield: 2.3% on $36.00 stock price Payout ratio 50% 52% 60% 57% 37% 36% 42% 37% Yield 3.3% 2.8% 3.4% 4.5% 2.3% 2.9% 2.7% 2.3%

9. Questar Market Resources is our growth driver Rockies Midcontinent Rockies 76% Midcontinent 66% Rockies Midcontinent *Nonregulated proved reserves and production (excludes Wexpro)

10. We’ve grown reserves more than fivefold over the past decade 2004 Production Guidance 97-102 Bcfe* Bcfe Production* 10-year CAGR: 9.1% Canada sale Proved reserves* 10-year CAGR: 17.8% 93 94 95 96 97 98 99 00 01 02 03 04 *excludes Wexpro

11. Questar E&P has maintained cost discipline in a higher price environment E&P Statistical Highlights 10-yr CAGR 1993* 2003 2002 $227 1,159 93 12.5 $3.66 0.95 0.29 0.49 0.23 $1.96 0.33 $2.29 15.2% 17.8% 9.1% 6.3% 1.7% 1.5% 5.0% 3.4% 3.8% $212 1,113 96 11.6 $2.72 0.91 0.27 0.55 0.27 $2.00 0.17 $2.17 • EBITDA ($ millions) • Year-end reserves (bcfe) • Production (bcfe) • Reserve-life index (yrs) • Average realized price/mcfe • DD&A rate • G&A costs • LOE • Allocated interest Total controllable costs • Production taxes Total pre-FIT cost $55 225 39 5.8 $1.99 0.80 0.25 0.30 0.05 $1.40 0.18 $1.58 ** *Not restated for successful-efforts accounting ** Reflects 2002 Canada and San Juan basin asset sales

12. We’ve maintained a high success rate while expanding drilling activity Total Net Wells* 160 146 Dry & abandoned holes 135 Successful wells 93 94 71 46 24 Success rate: 90% 85% 89% 91% 90% 91% 96% 93% *includes Wexpro drilling

13. Our Pinedale project will drive production and earnings growth Pinedale Anticline Focus Area Jackson Concentrated asset Proven play Deep potential Downspacing potential Developed infrastructure Gathering and processing Powder River Basin Wind River Basin Wind River Mtns ID Green River Basin Overthrust Belt UT Great Divide Basin Rock Springs Uplift Cheyenne Washakie Basin WY Salt Lake City CO Sand Wash Basin Uinta Mtns Vernal D-J Basin Uinta Basin Denver Piceance Basin Uinta Basin UT CO

14. Our Pinedale project provides a solid platform for long-term growth • 443 Bcfe proved reserves (excl. Wexpro) at 12/31/03 • 250 to 430 locations depending on spacing • 20-acre downspacing likely • Reserves: 8 Bcfe/well • Low finding costs ($.50-.60/Mcfe) • QEP net production (excl. Wexpro) • 2003: 15.2 Bcfe • 2002: 8.6 Bcfe • 30-well 2004 drilling plan WYOMING Wind River Questar’s acreage 62% WI in 14,800 acres Uplift Pinedale Jonah Field LaBarge Complex 10 Miles

15. Depth = 14,000 feet We’re using directional drilling from pads at Pinedale to significantly reduce surface impact Shared Production Facility on Surface Pad 2,100 foot radius of “reach” Up to 16 Wells from One Surface Pad Sandstone Gas Reservoirs

16. Year-round drilling is a “win-win-win” for the environment, the community and Questar Number of Active Pads to Drill 40 Wells Per Year Seasonal Operations Year-Round Operations NO. OF PADS

17. Uinta Basin provided about 1/3 of 2003 nonregulated production Vernal Greater Altamont/Bluebell Wonsits Valley Red Wash • Wasatch gas • Green River oil • 304 Bcfe proved reserves at 12/31/03 • QEP net production:: • 2003: 29.0 Bcfe • 2002: 26.8 Bcfe Typical well IP’s at 1 MMcf/d • 118,275 net leasehold acres • Over 120 Wasatch locations yet to drill • Currently evaluating deep potential • Emerging Green River gas play Greater Monument Butte Greater Natural Buttes Island COLORADO UTAH Gas Oil Questar acreage

18. Pinedale Rock Springs Uplift Moxa Arch We hold significant acreage in the greater Green River Basin • Deep potential • Downspacing potential • Stratigraphic plays on flanks of old fields • Hydraulic fracturing • 3-D seismic • Coal-bed methane QMR’s Acreage Position 632,000 gross acres 418,000 net acres QMR Acreage Gas Fields

19. We intend to grow our Midcontinent E&P business • Less basis (price) risk than the Rockies • Long-lived reserves and production • In-house knowledge and experience • Multi-target drilling opportunities (stacked pay) • Abundant pipeline/gathering infrastructure • 1,828,000 gross/423,000 net leasehold acres • Private land ownership and year-round access

20. Wexpro’s earnings are not sensitive to commodity prices . . . Capital Expenditures Operating Costs Successful wells & Dry holes non-drilling costs Excluded from investment base cost absorbed by shareholders via higher depreciation Wexpro receives a return of and earns a return on its investment base Questar Gas reimburses cost of producing reserves . . . Wexpro earns a 19-20% after-tax return on its investment base

21. Wexpro’s growing investment base yields growing net income $ Millions $173 Investment base $165 $161 Net income $125 $109 $98 $73 $33 $31 $28 $24 $21 $19 $17 * Before FAS 143 charge ($32.6MM after)

22. Questar Gas cities served Questar Gas system Questar Pipeline system Other pipeline systems Producing basins Our regulated companies provide a stable earnings base • Questar Pipeline - Core system 1,907 miles Southern Trails (East) 488 Overthrust 88 Total system 2,483 miles - Total daily capacity: 2,920 Mdth • Storage capacity: 139.5 Bcf - Rate base: $565 million • Questar Gas - Cities served: 277 - Customers: 770,500 - Deliveries: 132 MMdth - Rate base: $617 million WYOMING IDAHO NEVADA Salt Lake City UTAH COLORADO CALIFORNIA Southern Trails Pipeline ARIZONA NEW MEXICO Long Beach

23. Central Midwest Western Western 15,000 15,000 Southeast Southeast 12,000 12,000 Southwest Southwest 9,000 9,000 6,000 6,000 3,000 3,000 0 0 New LNG Imports = Direction of Flow New pipelines will be needed to move Rockies gas to distant markets Source: EIA and others

24. We’ve extended and expanded our pipeline system • Transportation volumes up 7% in 2003 • Tie Line 112 • 52,000 dth/d expansion to QGC • Cost $13MM, revenue $3.3MM • In service – Oct. 2003 • Northern System Expansion • 85,000 dth/d to Kern River • Cost $4.1MM, revenue $1.4MM • In service – May 2003 • Southern System Expansion under development • Evaluating storage projects Northern expansion Northern system Tie Line 112 Salt Lake City Clay Basin Southern system Kern River UTAH Southern Trails Long Beach

25. Questar Gas customer growth has averaged 3% per year since 1985 Customers +2.7% Growth In 2003 …. and we must invest $70-80MM per year to keep pace with customer growth

26. We intend to improve QRS performance in 2004 • Improve returns on capital • Get contracts / expand our pipeline • Manage cost of new pipeline safety requirements • Resolve Southern Trails Pipeline • Resolve Utah gas-processing dispute without refund

27. Our credit ratings are strong; we will maintain strong ratings Moody’sS&P Senior unsecured debt ratings: Questar Gas A2 A+ Questar Pipeline A2 A+ Questar Market Resources Baa3 BBB+ Questar Corp - Short-term P2 A1

28. Our balance sheet is strong; we will maintain a strong balance sheet Capitalization (including short-term debt)($ Millions) $2,610 $2,372 $2,333 $1,876 $1,774 $1,692 Debt Equity Total debt % 50 50 49 59 51 47 Equity % 50 50 51 41 49 53

29. We generate strong cash flow to fund capex, dividend and debt reduction Cash Flow From Operations (before working-capital changes) ($ Millions) $469 $416 $328 $318 66% QMR 59% $230 67% 57% 54% QMR QRS QRS

30. 2004 capital budget reflects good investment opportunities funded from cash flow ($ Millions) $415 $335

31. Investors should monitor our progress toward 2004 goals Earn 12.0% ROA Grow nonregulated production 8% to 100 bcfe Drill and complete 30 Pinedale wells Grow proved reserves 3.5% to 1200 bcfe Hedge up to 80% of 2005 production at prices above 2004 Resolve Southern Trails Pipeline Resolve Questar Gas processing dispute without refund Earn 11.2% ROE in Questar Gas

32. AN INTEGRATED NATURAL GAS COMPANY Questar is built on a strong foundation This presentation contains forward-looking statements about the operations and expectations of Questar Corp. and its subsidiaries. Management believes they are reasonable expectations of the company’s performance. Actual results may vary materially from our stated expectations and projections. Additional information concerning the factors that could cause materially different results are found in Questar’s Form 10-K and 10-Q reports on file with the SEC, and in the company’s annual report.