The present research is concerned with studying agentive forms in English and their corresponding forms in Arabic in order to determine some points of similarity and difference ; particularly as far as form and syntactic function are concerned. The research pointed out that they are similar in the derivation process which both undergo. In English This process incorporates a large number of suffixes , some quasi suffixes and few morphological processes. In Arabic , this derivation is strictly associated with two patterns determined by the morphological structure of the verb , the sole source of derivation. As for the syntactic function of the agentive forms, it is confined to the nominal one in English while it extensively includes nominal and adjectival functions besides the basic verbal in Arabic.