In this study, by the application of cytosine arabinoside, caffeine, sodium salicylate and retinyl acetate to mice in their critical period of pregnancy, joint anomalies that were caused in fetuses are investigated. In the cytosine arabinoside applied group complete disappearance of upper extremity joint spaces and narrowing or complete disappearance of joint spaces in lower extremity was prominent. In caffeine applied group, in all upper extremity joints starting from articulatio humeri, there were abnormal conjunctions, in bones, missing injoint space in some areas were present. In lower extremity joints and bones similar findings were seen. In sodium salicylate applied group, complete disappearance of joint space and articulating surfaces disappearance of joint spaces between humerus-radius and ulna were striking, conjunctions in tarsometatarsal joints in some areas was also present. Narrowing of joint space in the retinyl acetate applied group was striking. Complete disappearance of articulatio manus and carpometacarpal joints were observed. Lower extremity joints and bone findings were accompanying these.