Abstract: The aim of the present study was to investigate the preventive effect of 4 weeks soy meal (±isoflavone) on post-menopausal cognitive deficiency and body weight alteration in ovariectomized (OVX)-6-hydroxy dopamine (6-OHDA)-induced animal model of Parkinson’s Disease (PD) which mimics status in menopause women. Female Wistar rats (250-300 g, 5-6 months old) were divided into 2 main groups. (1) Control; (2) OVX; included 5 subgroups that were pre-treated with 10 or 20 g soy with isoflavone in 30 g daily diet (10 and 20 groups, respectively), 10 or 20 g soy without isoflavone in 30 g daily diet (-10 and -20 groups, respectively) and 0 g soy (sham treated group) during 4 weeks after OVX. To induce animal model of PD in main second group (OVX rats) the substantia nigra pars compacta (SNpc) was lesioned by 6-hydroxydopamine (6-OHDA) (8 μg kg-1 4 μL-1 normal saline contains 0.1% ascorbate). All animals were trained in Morris water maze for evaluating the spatial learning and memory. The results indicated that pre-treatment of Parkinsonian rats with different doses of dietary soy meal (±isoflavone) improved the spatial learning and memory and prevents increasing the body weight after menopause significantly. Our data show that, long-duration dietary soy meal may have the potential neuroprotective effect against post-menopausal cognitive deficiency induced by degeneration of nigrostriatal dopaminergic system and constant body weight during post-menopausal life cycle.