With the growing world of business, the competition between similiar companies getting tighter. To maintain the viability of a company, it is required a good management of resources conducted by the mangement. Working Capital (WC) management is very important for a company, especially the turn-overs of WC and Account Receivable (AR) due to the effect in measuring its Return On Investement (ROI). The purposes of this research were to know: (1) the effect of working capital turnover to company return on investment, (2) the effect of accounts receivable turnover to company return on investment, (3) the effect of working capital and receivable turnover to company return on investment. The research method used were financial ratio analysis, correlation coefficient test, coefficient of determination test and hypothesis test. The data used in this study was secondary data sourced from financial statement PT. Merck Tbk period of 2009-2018. The result based of the multiple linear regression tests showed that simultaneously the turn-overs of WC and AR have no significantly affected the profitability of the company, Fcount > Ftable or 2.576 < 4.46. Partially, WC turnover has no significant effect on company return on investment, with tcount < ttable or 1,140 < 2.365 and AR turnover has no effect on company return on investment, with tcount < ttable or 1.847 < 2.365. Keyword: working capital turnover, account receivable turnover, return on investment, profitability, PT. Merck Tbk.