The aim of this paper is to analyze empirically the main determinants of delays to market approval of active substances in Europe. An interesting feature of this regulation is that it is based on both a decentralized examination by the rapporteur country and a centralized examination by the European Food Safety Authority (EFSA). Our econometric analysis is based on standard survival and competing risks models. The data cover 393 active substances reviewed between 1993 and 2013. We show that the review process is affected by regulatory factors, the characteristics of the active substances and the characteristics of agri-chemical firms. Log-logistic and log-normal survival models are the preferred parametric specifications, and the results suggest that the hazard function is non-monotonic over time.