We reviewed some moral hazard (MH) models applied to agri-environmental policies andidentified the main methodological aspects of the literature on this topics. Imperfect vsincomplete monitoring , static vs dynamic and single vs multiple agents models are the mainlines along which the literature has been organised analysing each component of a MH model.Most papers point out the role of farmers' risk aversion in mitigating MH. Others highlight thatthe observed high rate of compliance is still somewhat paradoxical given current enforcementstrategies with low fines and monitoring levels. Cross compliance confirm these findings andurges further studies on dynamic models and farmers' non profit maximising behaviour.