In the Netherlands agency work, that is working through a temporary work agency, has become increasingly popular over the past three decades. In other countries its popularity is also growing. This thesis investigates the importance of agency work for the Dutch economy. This is done from three viewpoints. First, a longitudinal analysis is conducted to find out if agency work can serve as a leading indicator of macro-economic developments. Secondly, the labor supply of agency workers is compared to that of other employees. Points of interest are the characteristics of agency workers, the choice for agency work and possible trade-offs between labor hours, wages and labor contracts. A labor supply model and several logit models are estimated. Thirdly, the demand for agency workers by firms in various economic sectors are examined. The issues include possible substitution effects between agency workers and other employees, the effect of agency work on the efficiency of the firm, and firms’ reasons, other than cost aspects, for using a temporary work agency. A labor demand model and several logit and tobit models are estimated.