Important changes in the productivity of lowland and upland rice are observed in the area around Lake Alaotra, the major rice basin of Madagascar, that compromise food security most seriously in a country that is already a net importer of this commodity. Current changes in management, as an adaptive response to shortening of cropping cycles, and higher production risks meet an increasing pressure on the land due to demographic growth in the region, largely due to immigration (Andrianjanaka, 2007). Less water available for irrigation and intensive erosion of hillside soils are the two major biophysical factors threatening the sustainability of irrigated and upland rice, respectively, in the region. The aim of this study is to analyse the impacts of climate change, its perception by farmers and the changes in agricultural practices associated to this as well as the role of the increasing population density. This paper presents some preliminary results on such changes.