Diphenylchloroarsine is readily obtainable in good yield, together with small quantities of phyenyldichloroarsine and triphenylarsine, by oxidation of phenylhydrazine with arsenic acid in presence of a suitable catalyst, followed by treatment with hydrochloric acid. Diphenylcyanoarsine can be prepared in excellent yield either by treatment of the chloro‐compound with potassium cyanide or the intermediate diphenylarsenoxide with hydrocyanic acid.