This study was undertaken to determine the improving effects of swimming training on brain ischemic lesions and muscle atrophies caused by middle cerebral artery (MCA) occlusion in male rats. Rats were divided into four groups: MS(MCAO plus swim), MC(MCAO plus control), SS(Sham plus swim), SC(Sham plus control). From 4d after induction, MS and SS rats were participated in swimming exercise during 30min. Rats were sacrificed 24h after last treatment and brain slices were prepared for TTC stained to assess lesion size, and also TA muscle were prepared for histochemical analysis. The infarct volumes of MS were significantly decreased than MC. The wet weights and relative wet weights to body weights of paretic side in MS were significantly heavier than MC. The relative wet weights to body weights in SC were significantly heavier than MC whereas no significantly differences between MS and SS. Increased percentages of type I and decreased percentages of type IIb were denoted in paretic sides than healthy sides of MS. The CSAs of type I in paretic sides of MS were significantly larger than MC and than healthy sides. These finding suggest that earlier started swimming training can prevent increasing infarct volume and improve muscle atrophy of TA induced MCAO.