This study was performed to investigate the changes in immune status of rats by dietary iron and regular exercise. Male Sprague Dawley rats (n = 40) were divided into 4 groups by dietary iron (Fe^(-), 5 ppm Fe vs. Fe^(+), 50 ppm Fe) and exercise (control vs. exercise). Rats were given experimental diets for 8 weeks. Regular treadmill exercise (6˚, 28 m/ min, 30 minutes duration) was given to exercise groups 5 days per week for 8 weeks. Iron deficient rats decreased hematocrit (47.5% vs. 39.8%) and hemoglobin concentration (16.0 g/dl vs. 12.3 g/dl) compared to iron sufficient rats and were in a marginal marginally iron-deficient-anemic status. Immunoglobulin(Ig) A level was significantly increased by regular exercise. IgG level was also significantly increased by regular exercise in Fe^(+) group, but was decreased in Fe^(-) group. Spleen cell proliferation by Con A stimulation showed an increasing tendency in exercising Fe^(+) group, but significant difference was not found. IL-2 concentration showed an increasing tendency with regular exercise, but statistical difference was not found. IL-2 and IFNy were not significantly affected by dietary iron level of this study. It is likely that regular exercise significantly increases plasma Ig A and sufficient supply of dietary iron is necessary for the enhancement of immune response with regular exercise.