The study is to undertake the analysis of impact of acquisition on the financial performance and stock return of acquirer companies in Malaysia. The period of study is from year 2005 to 2007 and the samples of companies used are the 49 companies listed on the main board of Bursa Malaysia. In the second part, the study considered the acquisition announcement date as day 0 and analyzed the impact of acquisition announcement on the stock return of acquirer company 20 days before and after acquisition announcement date.