Polyunsaturated fatty acids (PUFAs) have significant, cardioprotective effects against ischemia. Hempseed contains a high proportion of the PUFAs linoleic acid (LA) and alpha-linolenic acid (ALA) that may have opposing effects on post-ischemic heart performance. There are no reported data concerning the cardiovascular effects of dietary hempseed intake. A group of 40 male Sprague-Dawley rats were distributed evenly into 4 groups that were fed for 12 weeks a normal rat chow supplemented with either hempseed (5 and 10%), or palm oil (1%), or a 10% partially delipidated hempseed that served as a control. Plasma ALA and GLA levels were significantly elevated in the rats that were fed a 5 or 10% hempseed supplemented diet but in heart tissue, only ALA levels were significantly elevated in the rats fed these diets as compared to control. After the dietary interventions were completed, post-ischemic heart performance was evaluated by measuring developed tension, resting tension, the rates of tension development and relaxation, and the number of extrasystoles. Hearts from rats fed a hempseed supplemented diet exhibited significantly better post-ischemic recovery of maximal contractile function and enhanced rates of tension development and relaxation during reperfusion than hearts from the other groups. These hearts, however, were not protected from the occurrence of extrasystoles nor were the increases in resting tension altered during ischemia or reperfusion as a function of any dietary intervention. Our data demonstrate that dietary hempseed can provide significant cardioprotective effects during post-ischemic reperfusion. This appears to be due to its highly enriched PUFA content