The primitive cardiac loop of the stage 14 (Hamburger and Hamilton) chick embryo was subjected to brief vibratory stimuli that resulted in a broad spectrum of cardiovascular malformations. During the 17th day of incubation, both survival and anomaly rates were evaluated. Compared with control embryos (92%), vibration elicited mortality (75%) that was statistically highly significant (p less than 0.001). In addition, the anomaly rate (94%) among surviving embryos was also highly significant (p less than 0.001) relative to controls. Defects included straddling AV valves, variable sizes of VSD and DORV. Several possible explanations are presented concerning the etiology of these vibration-induced malformations.