Working capital represents the amount of funds invested in firms' current assets. Optimizing working capital management is a challenge and a necessity for firms especially today due to the demand volatility and limit access to bank credit. This paper investigates the relationship between working capital management and firms' performance in small and medium enterprises in Greece. The results suggests that an effective working capital management is a necessary component of firm's future growth and profitability. The analysis used data for a sample of 459 small and medium enterprises for the period from 2008 to 2012. The paper is organized as follows: in the next section we briefly present the problem based on literature review. This is followed by the presentation of research methodology and the data sources used in the analysis. The results are presented and discussed in section three. Last section summarizes the conclusions and presents further opportunities for research.