Thursday February 25, 2010 For immediate release

Release: Series 11 Release 4 TSX Venture: TDC

VANCOUVER, British Columbia (Thursday February 25, 2010) -- Tyhee Development Corp.

(TSX Venture, TDC) (the “Company”) has closed on 4,830,000 units of the 21,030,000 unit

financing announced on February 16, 2010. One million of these warrants had been exercised

earlier and were not available to participate in the financing. In this closing 4,830,000 units were

subscribed for and $724,500 was received. 4,830,000 warrants, exercisable at $0.15, were

submitted for cancellation. A total of 4,830,000 shares and 2,415,000 warrants exercisable at

$0.25 anytime prior to July 15, 2011 have been issued. All securities are subject to a four

month hold. Funds from the private placement will be used for further exploration and

development of the Company’s advanced-stage Yellowknife Gold Project and for general

corporate purposes.

Tyhee currently has three diamond drills on its Yellowknife Gold Project, two operating on the

Clan Lake Main Zone, and one operating on the Ormsby Zone. “These funds, together with

those raised in December 2009 will enable Tyhee to continue to advance its Yellowknife Gold

Project.” reports Dave Webb, President & CEO. “Tyhee has completed the first six of the

current 33 drillhole program at Clan Lake. Tyhee has an indicated resource of 354,000 ounces

at the Clan Lake Main Zone. The drill core is currently being processed and the first assays

should be received by mid March. Additionally, two more drillholes are planned at the Ormsby

Zone.”

This news release does not constitute an offer to sell or a solicitation of an offer to sell any of

the securities in the United States. The securities have not been and will not be registered

under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”) or any

state securities laws and may not be offered or sold within the United States or to U.S. Persons

unless registered under the U.S. Securities Act and applicable state securities laws or an

exemption from such registration is available.

Tyhee Development Corp. is a gold exploration and development company working in the

historic Yellowknife Gold Camp, NWT, Canada. It is the largest property holder in this camp

and has the largest exploration and development program underway in the region. Its principal

asset is the Yellowknife Gold Project includes the Nicholas Lake, Ormsby, Bruce, Goodwin

Lake, and Clan Lake Gold Zones. All are located on mineral claims and mining leases 50 to 90

km north of Yellowknife, NWT. (Note: only Nicholas Lake and Ormsby Zones are been included

for permitting purposes).

For further information please contact:

David Webb, President and CEO Jay Bedard

Tel: 604-681-2877 Tel: 416-977-7778