High temperature molten salt electrosynthesis is a promising method for preparing thin layers of metallic or composite compounds. In this case no post heat treatment (modifying the interface composition) is needed. In this work, we report the electrowinning of ZnSe which is performant for realizing diode lasers and solar cells. Thin films containing up to 90% well crystallized ZnSe with Se/Zn around 1.1 and a grain size equal to 1 mu m was obtained in the molten mixture NaCl-CaCl2 fused at 550 degrees C. Optical properties are currently studied.