In this study we analyzed the effect of 2008 financial crisis on firm performance. With this aim we used manufacturing sector in Turkey. In our study we used 119 firms traded on Borsa Istanbul and quarterly data belong to 2004-2012 period. In this study we examined the period before and after 2008 crisis. We applied one sample kolmagorov-smirnov test to know whether the data has normal distribution. Also we used T-Test Analysis to compare average of the data. At the result of analysis financial ratios that accounts receivable turnover, liquidity, net working capital, short term debt / Total Debt, Financial Leverage Ratio, founded different in before and after year 2008, according to year 2008.