This book entitled ” Hydro-agricultural development: Diagnosis and assessment of environmental risks in Benin ” is a participatory action research project of the ” Environment and Climate Change ” program of the Action Center for Food Security and Sustainable Development (Casad-Benin). It provides a better understanding of the characteristics of hydro-agricultural developments and associated environmental risks. After having identified the different types of hydro-agricultural development (hydro-agricultural development by gravity, pumping and manual watering); the sources of the environmental risks of their development have been identified and analyzed. It appears that the different practices have led to a degradation of the plant cover thus causing its regression and a decline in soil fertility. The book proposes sustainable management measures to reduce the risks of hydro-agricultural development on the environment.