Background and purpose: Parkinson 's disease, one of the most common neuromotor disorders, is caused by the progressive destruction of the dopaminergic neurons of the basal nuclei. Whey is considered a rich source of amino acids and peptides with biological properties. Considering the beneficial effects of exercise on the inhibition and recovery of neuronal damage, the present study investigated the effect of swimming exercise and whey administration on motor dysfunction and gene expression of apoptotic factors of the striatumin the Parkinson's disease model induced with retenon.