XTO Increases Proved Reserves to a Record 11.29 Tcfe, Up 32%

XTO Energy Inc. reported that Miller and Lents, Ltd., independent petroleum engineers, estimate XTO's proved oil and gas reserves at December 31, 2007 to be a record 11.29 trillion cubic feet of gas equivalent (Tcfe), up 32% compared with 8.55 Tcfe at December 31, 2006. Natural gas reserves increased 36% to 9.44 Tcf, and natural gas combined with natural gas liquids of 67 million barrels equaled 87% of total reserves. Oil reserves increased 13% to 241 million barrels. Proved developed reserves accounted for 66% of total proved reserves on an equivalent basis.

During 2007, XTO Energy added 3.41 Tcfe at a cost of $2.03 per thousand cubic feet of gas equivalent (Mcfe), replacing 513% of production. The Company's development program replaced 308% of production or 2.05 Tcfe at a cost of $1.64 per Mcfe. Excluding unproved property additions from leasing activities, development costs were $1.36 per Mcfe.

"These results highlight the strength of XTO's property base and the efficiency of our ongoing development campaign," stated Bob R. Simpson, Chairman and Chief Executive Officer. "As we look ahead, our teams are confident in the Company's resource potential and have defined growth plans. We are also committed to securing choice 'bolt-on' acquisitions to continue expanding our opportunity set. Given these projections, and the market outlook on commodity prices, we are targeting proved reserves of 15 Tcfe by the end of 2009. This reserve growth goal reflects two-thirds coming from development program additions and one-third from acquisitions."