Ultra Petroleum Increases Proved Reserves By 32 Percent

Ultra Petroleum says that as of the year-ended December 31, 2005, its total proved oil and gas reserves were 2.022 trillion cubic feet of gas equivalent (Tcfe), up 32 percent from 1.528 Tcfe as at December 31, 2004. Year-end 2005 proved reserves include 1.900 Tcf of natural gas and 20.265 million barrels of oil (Mmbbls). Proved plus probable reserves at December 31, 2005 totaled 6.295 Tcfe an increase of 80 percent from December 31, 2004 levels of 3.492 Tcfe. The estimated future net revenue from proved reserves discounted at 10 percent ("SEC PV-10") is $5.446 billion based on year-end Opal, Wyoming price of $7.71 per million British Thermal Unit (MMBtu) or $8.00 per wellhead thousand cubic feet of gas (Mcf), $57.10 per wellhead barrel in Southwest Wyoming and $48.74 per barrel for Bohai Bay, China crude. All reserves were prepared by Ultra Petroleum's third party independent reserve consultants.

Proved reserves from the company's Wyoming properties were 1.991 Tcfe, with 1.900 Tcf of natural gas and 15.205 Mmbbls of condensate. Only those locations included in the company's budgeted three-year drilling plan are included as proved undeveloped reserves in the report. Locations that are not in the three-year budget, but would otherwise be classified as proved are included in the probable category. The proved plus probable reserves totaled 6.240 Tcfe. For the 7th consecutive year Wyoming reserve estimates were prepared by the independent reserve engineering firm of Netherland, Sewell and Associates, Inc.

Proved reserves from Ultra Petroleum's first four producing fields in Bohai Bay, China, totaled 5.061 Mmbbls and proved plus probable reserves totaled 9.211 Mmbbls. Ultra Petroleum began booking Bohai Bay, China reserves in 2004 and Ryder Scott Company has prepared the China reserve report for the past two years.

"Again in 2005, Ultra delivered what is likely the industry's highest organic proved reserve growth both in percentage terms and in absolute volumes. In addition, all of the locations we drilled in 2005 were successes, which continue to highlight the low risk nature of our asset base in Wyoming. The 2005 2P (proved plus probable) reserve growth reflects the positive impact of our down spacing effort in the Pinedale Anticline and Jonah Field. We have more than doubled our inventory of locations in Wyoming to 2,867 giving us over 17 years of drilling at our current rate. Despite the impressive increase in reserves, we believe the risk profile of our asset base has been reduced. In accordance with Ultra's three-year planning and budgeting cycle, proved undeveloped reserves include only economic locations that are offsets to producing wells and are forecast to be drilled during the next three-years.

With over 6.295 Tcfe of net proved and probable reserves, we are positioned to easily continue to deliver industry leading organic proved reserve and production growth over the next several years. And as we finish gathering the necessary data from the 10-acre pilot programs at Pinedale and prepare to drill our own deep-test well, we'll continue to develop a much clearer picture of how large the reserves from the currently identified fairway may become," stated Michael D. Watford, Chairman, President and CEO.

                            Ultra Petroleum Corp.
                                   Reserves
                              December 31, 2005

    Corporate
                                                             Gross   Future
                      Net Gas Net Oil Net Equiv.   PV10    Economic   Capex
    Reserve Category   (BCF)   (MMB)    (Bcfe)     (MM$)     Wells    (MM$)
    PDP               614.513  7.312   658.385  $2,012.419    384      $0.839
    PDNP               21.078  0.259    22.632     $68.511     14      $8.103
    PUD             1,264.632 12.694 1,340.796  $3,364.653    454  $1,111.491
    Total Proved    1,900.223 20.265 2,021.813  $5,445.583    852  $1,120.433

    Probable        4,053.536 36.578 4,273.004  $6,137.660  2,116  $5,883.478
    2P (PV. + PB.)  5,953.759 56.843 6,294.817 $11,583.243  2,968  $7,003.911

    EST.
     (PV. + .5 PB.) 3,926.991 38.554 4,158.315  $8,514.413  1,910  $4,062.172




    Pinedale Anticline, WY
                                                             Gross   Future
                      Net Gas Net Oil Net Equiv.   PV10     Economic  Capex
    Reserve Category   (BCF)   (MMB)    (Bcfe)     (MM$)     Wells    (MM$)
    PDP               547.988  4.295   573.758  $1,764.401    293       $ ---
    PDNP               21.078  0.168    22.086     $66.947      9      $8.084
    PUD             1,181.145  9.449 1,237.839  $3,020.946    402  $1,050.452
    Total Proved    1,750.211 13.913 1,833.683  $4,852.294    704  $1,058.536

    Probable        3,894.094 31.153 4,081.012  $5,648.022  1,977  $5,693.752
    2P (PV. + PB.)  5,644.305 45.066 5,914.695 $10,500.315  2,681  $6,752.288

    Prepared by Netherland, Sewell and Associates, Inc.



    Jonah Field, WY
                                                             Gross    Future
                      Net Gas Net Oil  Net Equiv.   PV10    Economic   Capex
    Reserve Category   (BCF)   (MMB)    (BCFE)      (MM$)    Wells     (MM$)
    PDP                66.525  0.624    70.269   $ 174.881     43        $---
    PDNP                  ---    ---       ---        $---      0        $---
    PUD                83.487  0.668    87.495   $ 284.136     32     $55.082
    Total Proved      150.012  1.292   157.764   $ 459.018     75     $55.082

    Probable          159.442  1.276   167.098   $ 380.621    111    $189.726
    2P (PV. + PB.)    309.454  2.568   324.862   $ 839.639    186    $244.808

    Prepared by Netherland, Sewell and Associates, Inc.



    Bohai Bay, China
                                                             Gross     Future
                      Net Gas Net Oil Net Equiv.    PV10    Economic   Capex
    Reserve Category   (BCF)   (MMB)    (BCFE)      (MM$)    Wells      (MM$)
    PDP                   ---  2.393    14.358     $73.137     48      $0.839
    PDNP                  ---  0.091     0.546      $1.564      5      $0.019
    PUD                   ---  2.577    15.462     $59.570     20      $5.957
    Total Proved          ---  5.061    30.366   $ 134.271     73      $6.815

    Probable              ---  4.150    24.900   $ 109.018     28        $---
    2P (PV. + PB.)        ---  9.211    55.266   $ 243.289    101      $6.815

    Prepared by Ryder Scott Company

Ultra Petroleum is an independent, exploration and production company focused on developing its long-life natural gas reserves in the Green River Basin of Wyoming, and oil reserves in Bohai Bay, offshore China. Ultra Petroleum is listed on the American Stock Exchange under the symbol "UPL" with 155,075,864 shares outstanding as of the date of this release.