A study was made on the effect of temperature on the electrodeposition of hard chromium on 1045 steel within a range of 30° to 60°C, as shown by variations in reaction yield, surface hardness, and depositional grain size. Increase in temperature produced a decrease in faradic yield of the reaction of between 17% and 9%, an increase in hardness from 550 to 700 Brinelli, and a decrease in deposited chromium grain size from 278 to 32.4 urn. The most notable effect of temperature difference was observed between 30° and 40°C. Chrono-potentiometric and potentiodinamic linear sweep were measured at 30°C, 40°C and 50 °C in an attempt to explain this behavior. The results obtained suggested the formation of a compact film typical of a nucleation process in chromium electrodeposition. An increase in temperature affects the formation of this film, decreasing its thickness and distributing it in a more homogeneous manner over the steel, as shown by a decrease in the grain size of the chrome deposited