This study aims to find the impact of working capital management on the financial performance of industrial corporations in Palestine. We used a sample of 13 industrial firms that were listed on the Palestine Securities Exchange for years 2002 to 2018. We used cash conversion cycle and its components as independent variables and both return on assets and return on equity as dependent variables. Moreover, since deferred checks are vital in commercial transactions in Palestine, we tried to take into consideration the effect of including checks under collection and deferred checks on performance. Eight panel econometric models were estimated. The study found that the cash conversion cycle and firm size have a significant positive impact on the profitability of industrial corporations, while leverage is significantly negative with profitability. In addition, it was found that Palestinians firms maintain a sizable working capital which may be due to a long cash conversion cycle (about nine months average) and to conservative policies due to instable economic and political conditions. These findings are consistent with several previous studies from other countries such as Jordan, Pakistan, India and Portugal.