SEN Sentinel Rock Oil Corporation

Sentinel Rock Oil Corporation ("Sentinel" or the "Company") (TSX VENTURE: SEN) is pleased to announce that it has filed on Sedar it's reserve report for the period ended July 1, 2008 as evaluated by DeGolyer and MacNaughton Canada Ltd. ("D&M") and prepared in accordance with National Instrument 51-101 Standards of Disclosure for Oil and Gas Activities.

This report documents the results achieved by the company on its activities previously reported throughout 2007 - 2008 from its ongoing drilling programs.

Sentinel's President and CEO Tyler Cran commented, "We are pleased and encouraged by the reserve increases in all categories. As a result of our last drilling operations, we have established Proved Reserves, our Proved plus Probable Reserves (2P) have increased by 1,770% and our Proved plus Probable plus Possible (3P) Reserves by over 534%. The combined reserves have increased from 1.477 to 5.307 MMboe and are consistent with our strategy of growing the resource base of the company. This reserve growth positions us well to take advantage of the current strong developing market for heavy oil."

Cran also commented "The drilling activity and results from the drilling program were on plan as well as in line with expectations that management had set out at the beginning of the program."

The Reserves report will be available at www.sedar.com.

RESERVES REPORT

Based on reserves reports prepared by D&M, using forecast prices and
costs, Sentinel's Gross Reserves for July 1, 2008 as compared to the
previous year end are as follows.

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Dollars - Company share                     2007           2008    % Change

Proved                              $          0  $     528,000

Proved + Probable                   $  2,266,000  $  40,119,000      1,770%

Proved + Probable + Possible        $ 21,063,000  $ 112,376,000        534%
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oil/STB - company share

                                            2007           2008    % Change

Proved                                         0              0          0%

Proved + Probable                        291,265      1,605,660        551%

Proved + Probable + Possible           1,472,591      4,972,005        338%
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gas/MMCF - company share

                                            2007           2008    % Change

Proved                                         0            145

Proved + Probable                            144            851        591%

Proved + Probable + Possible                 763          2,012        264%
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Combined Gas and Oil to standard BOE

                                            2007           2008    % Change

Proved                                         0         24,167

Proved + Probable                        292,129      1,747,493        598%

Proved + Probable + Possible           1,477,169      5,307,338        359%
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NAV Calculations

shares outstanding 28,264,431               2007           2008    % Change

Proved + Probable (2P)                    $ 0.08         $ 1.42      1,770%

Proved + Probable + Possible (3P)         $ 0.75         $ 3.98        534%
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NAV Calculations

fully diluted 30,426,931                    2007           2008    % Change

Proved + Probable (2P)                    $ 0.07         $ 1.32      1,770%

Proved + Probable + Possible (3P)         $ 0.69         $ 3.69        534%
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- The net present value of Sentinel's proved plus Probable reserves increased to $40.12 million, a 1,770% increase while the NPV of the total Proved plus Probable plus Possible reserves increased to $112.37 million, a 534% increase.

(1) Proved Reserves are those reserves that can be estimated with a high degree of certainty to be recoverable. It is likely that the actual remaining quantities recovered will exceed the estimated proved reserves.

(2) Probable Reserves are those additional reserves that are less certain to be recovered than proven reserves. It is equally likely that the actual remaining quantities recovered will be greater or less than the sum of the proven plus probable reserves.

(3) Possible Reserves are those additional reserves that are less certain to be recovered than probable reserves. There is only a 10-percent probability that the quantities actually recovered will equal or exceed the sum of the proven plus probable plus possible reserves.

(4) The Net Present Value (NPV) based on D&M Forecast Pricing and costs, before taxes, discounted at 10%. The estimated NPV does not necessarily represent the fair market value of our reserves. There is no assurance that forecast prices and costs assumed in the D&M evaluations will be attained, and variances could be material.

Additional information on Sentinel Rock Oil Corporation is available on the Company's website at www.sroc.ca.

All references in this release to BOE's are based on a 6 to 1 conversion ratio. Boe's may be misleading, particularly if used in isolation. A BOE conversion of 6 Mcf:1 bbl is based on an energy equivalency conversion method primarily applicable at the burner tip and does not represent a value equivalency at the wellhead.

Sentinel is a Calgary, Alberta based oil Exploration Company focusing on heavy oil with operations currently located in Northern Alberta and mid west Saskatchewan.

This news release contains forward-looking information. Forward-looking information is generally identifiable by the terminology used, such as "expect", "believe", "estimate", "should" "anticipate" and "potential" or other similar wording. Forward-looking information in this news release includes, but is not limited to, references to: well drilling programs and drilling plans, estimates of reserves and potentially recoverable resources, and information on future production and project start-ups. By their very nature, the forward-looking statements contained in this news release require Sentinel and its management to make assumptions that may not materialize or that may not be accurate. The forward-looking information contained in this news release is subject to known and unknown risks and uncertainties and other factors, which could cause actual results, expectations, achievements or performance to differ materially, including without limitation: imprecision of reserve estimates and estimates of recoverable quantities of oil, changes in project schedules, operating and reservoir performance, the effects of weather and climate change, the results of exploration and development drilling and related activities, demand for oil and gas, commercial negotiations, other technical and economic factors or revisions and other factors, many of which are beyond the control of Sentinel. Although Sentinel believes that the expectations reflected in its forward-looking statements are reasonable, it can give no assurances that the expectations of any forward-looking statements will prove to be correct.

28,264,431 common shares issued

The TSX Venture Exchange has neither approved nor disapproved the contents of this press release. The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.

Contacts: Sentinel Rock Oil Corporation Tyler Cran President and CEO (403) 538-8441 Sentinel Rock Oil Corporation Bryce Bonneville Vice President Business Development (403) 538-8441 Website: www.sroc.ca