Activision Inc. has agreed to buy DemonWare Ltd., an Irish videogame software designer, the Santa Monica video game publisher said Tuesday.

Privately held DemonWare, based in Dublin, will operate as a subsidiary of Activision, with the company’s top managers joining Activision’s management team. The transaction is expected to be completed by June 2008. Terms of the deal were not disclosed.

Shares in Activision were up 33 cents to $16.71 Tuesday in afternoon trading on the Nasdaq.