Abstract. Working capital is directly related to the operational activities of the company to produce goods. To be able to properly manage its working capital, the company should determine what factors that can affect working capital. Actually, there are many factors that affect working capital management but the factors that used in this study are firm size, leverage, firm growth, cash flow, profitability, capital expenditure, and GDP. Meanwhile, working capital management is reflected by the cash conversion cycle. By taking samples at manufacturing companies listed in Indonesia Stock Exchange period of 2010 -2014, it is found that there are a significant effects of firm size, firm growth, cash flow, profitability, and GDP toward working capital. While the leverage and capital expenditure shows insignificant effect.