The Working Capital Management (WCM) has an important role in the firm’s success or failure because it directly effects the overall business health of the firm. This study examined the impact of WCM on profitability and shareholders wealth using the 50 companies listed in different sectors on the Colombo Stock Exchange (CSE) from period 2010 to 2015. This sample represents 47% of the selected sectors of CSE. The profitability of the company is measured using gross operating profit (GOP) and shareholders wealth measured by Tobin’s Q (TQ) ratio. The WCM is measured using five independent variables namely stock holding period (SHP), debtors’ collection period (DCP), creditors’ settlement period (CSP), cash conversion circle (CCC) and current assets ratio (CAR). Further, three additional variables such as firm size (SIZE), leverage (LEV) and earnings yield (EY) are employed as controlling variables to capture the impact of other performance of the companies. The data were analyzed using ordinary least square (OLS) and panel data regression models. These regression models reveal that there is a significant negative relationship between CCC and dependent variables (GOP & TQ). Further, this relationship has been confirmed by the major components of CCC Such as SHP, DCP. Firm size also positively and significantly effects on the firm GOP while negatively effects on the TQ. Further, they revealed that there is a significant positive relationship between LEV and TQ. The study finds that the shareholders' wealth and profitability can be increased through the efficiency of WCM.