We present the results of near-infrared imaging of the dwarf spheroidal galaxies Fornax and Leo I as part of a photometric survey of stellar populations in Local Group dwarf galaxies. Wide-field observations in the J, H, and $K_s$ bands have been obtained with the SOFI camera at the ESO NTT at La Silla, Chile. The aim of this project is to study the evolution of Local Group dwarf spheroidal galaxies, with special regard to star formation at intermediate epochs. The near-infrared data, together with optical catalogs from the Padova Local Group wide-field survey, provide a very large color baseline ideal to study the properties of red giant branch (RGB) and asymptotic giant branch (AGB) stars.