This study examined the prevalence of post-traumatic stress disorder (PTSD) in a sample of 100 Israeli myocardial infarction (MI) patients. Chronic PTSD was diagnosed in 16% of these patients and acute (PTSD) in 9%. The appearance of PTSD following MI was found to be related to the following variables: ethnic background; prior traumatic experiences, including prior MI; and anticipation of disability following MI. Objective measures of MI severity were not related to propensity to develop PTSD. The presence of PTSD correlated with self reports of dysfunction in these MI patients and may account for the majority of failures in rehabilitation.