FOR IMMEDIATE RELEASE
July 5,2010

Notice on Determination of Details of Stock Options (Stock Acquisition Rights) to be Allotted

Notice on Determination of Details of Stock Options (Stock Acquisition Rights) to be Allotted
Eisai Co., Ltd. (Headquarters: Tokyo, President & CEO: Haruo Naito, “Company”) announced today that the details of Stock Options to be allotted to Directors, Executive Officers and employees of the Company in accordance with the resolution of the Board of Directors' Meeting (see III. below) held on June 18, 2010 have been determined as follows:

I. Eisai Co., Ltd. No. 9-1 Stock Acquisition Rights (Directors and Executive Officers)

1. Allotment date of stock acquisition rights:

July 5, 2010.

2. Total number of shares included in the allotment of stock acquisition rights:

1,440

3. Recipients and the number of recipients of the allotment and the number of stock acquisition rights allotted

4. Class and number of shares to be issued or transferred upon exercise of stock acquisition rights

Shares of common stock 144,000
(The number of shares to be issued or transferred upon exercise of each stock acquisition right shall be 100 shares.)

5. Amount of assets to be contributed upon exercise of stock acquisition rights

The amount to be paid for each share (the Exercise Price) ¥2,981
The amount to be paid for each stock acquisition right ¥298,100
(The Exercise Price is the average of the closing price of the common stock in the regular trading thereof on the Tokyo Stock Exchange for each day of the month preceding the month on the allotment date of July 5, 2010)

II. Eisai Co., Ltd. No. 9-2 Stock Acquisition Rights (Employees)

1. Allotment date of stock acquisition rights:

July 5, 2010.

2. Total number of shares included in the allotment of stock acquisition rights:

1,750

3. Recipients and the number of recipients of the allotment and the number of Stock acquisition rights allotted.

4. Class and number of shares to be issued or transferred upon exercise of stock acquisition rights

Shares of common stock 175,000
(The number of shares to be issued or transferred upon exercise of each stock acquisition right shall be 100 shares.)

5. Amount of assets to be contributed upon exercise of stock acquisition rights

The amount to be paid for each share (the Exercise Price) ¥2,981
The amount to be paid for each stock acquisition right ¥298,100
(The Exercise Price is the average of the closing price of the common stock in the regular trading thereof on the Tokyo Stock Exchange for each day of the month preceding the month on the allotment date of July 5, 2010)

III. Contents of the resolution of board of directors on June 18, 2010.

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