In this work, the in vivo effect of nitrosomorpholine on the rat kidney alanine and aspartate transaminases and creatine kinase activities during a definite course to be effective pharmacologically was injected to mice intraperitonally. For the controls, physiological serum was injected likewise. The enzyme activities were followed up during 30 hours at definite time of interwals. There were time releated significant increases in the activities of aspartate and alanine transminases but decrease was observed at the creatine kinase activities Keywords :