This study analyzes the comparison of the company's financial performance before and after the acquisition of five companies listed on the Indonesia Stock Exchange, namely PT Astra Otoparts Tbk, PT Bayan Resources Tbk, PT Indospring Tbk, PT MNC Land Tbk, and PT Telekomunikasi Indonesia Tbk. The analysis period includes five years before (2008-2012) and five years after the acquisition (2014-2018). The research method uses financial ratios such as Current Ratio (CR), Debt to Equity Ratio (DER), Total Assets Turnover (TATO), Return on Assets (ROA), Return on Equity (ROE), Net Profit Margin (NPM), and Earning Per Share (EPS). Hypothesis testing is done with the Kolmogorov-Smirnov normality test, paired sample t-test, and Wilcoxon Signed Rank Test. The results showed that there were significant differences in several financial ratios between the pre- and post-acquisition periods. The EPS ratio decreased significantly after the acquisition with a significance value of 0.002. Meanwhile, ROA and TATO did not show significant differences. Overall, acquisitions have an impact on changes in financial performance, both positive and negative. This study provides important implications for investors and management in making strategic decisions related to acquisitions. The results can be used to evaluate the impact of acquisitions on company performance.