Swimming is frequently preferred as an exercise model for small laboratory animals and as a health promotion exercise for ordinary people. The purposes of the present study are to examine the preischemic and post-ischemic training effects of swimming exercise on infarction in rats. For the preischemic training effect, rats were randomly assigned to either of the 2 groups (n=9 for each group): control and pre-ischemic swim training for 2 weeks. For the post-ischemic training effect, rats were divided into 2 groups (n=9 for each group): control and post-ischemic swim training for 2 weeks. Cerebral infarction was induced by middle cerebral artery occlusion (MCAO) for 60 min, followed by reperfusion. After the predetermined period (24 hours or 2 weeks), rats were killed and brain slices were then stained to assess lesion size. Neurological examination was performed before killing. Pre-ischemic swim training for 2 weeks can reduce the infarction size and neurological deficits caused by MCAO (P < 0.05). However, the post-ischemic swim training for 2 weeks did not result in a better recovery compared with the spontaneous recovery. The present study provides evidence that pre-ischemia swim training increases ischemia tolerance in an animal model of cerebral ischemia.