This study aims to analyze the performance of companies doing mergers and acquisitions that proxies by Return on Capital Employed (ROCE), Return on Equity (ROE), Operating Profit Margin (OPM), Net Profit Margin (NPM), EPS (Earnings Per Share), PER (Price Earning Ratio). This study uses the sample based on 90 companies in Indonesia manufacturing industries for the period from 2007 to 2012. Hypothesis testing is done by using the paired t test. We had documented the results of the study findings of the performance of the company which showed the distinction between two conditions, pre mergers and acquisitions when compared with post mergers and acquisitions of companies. However, many out of the results are not statistically significant.