The study investigated the effects of 16 weeks of exercise training on s-IgA in a population of low-functioning elderly. Forty-nine volunteers were randomly divided into 4 groups: strength training (ST), aerobic training (AT), a combination (CT), or control (C). ST demonstrated a significant increase in s-IgA from pre to post and a significant increase in the secretion rate from pre to mid and post. AT demonstrated a significant increase in s-IgA from pre to mid to post with no subsequent change in the secretion rate. There were no significant changes across time in CT or C, but C had consistently lower s-IgA values at post than did CT, ST, or AT, and the secretion rate was significantly higher in CT than C at mid and post. The results demonstrate that moderate exercise has a positive effect on mucosal immunity as measured by s-IgA in low-functioning elderly, suggesting a greater resistance to upper respiratory-tract infection with involvement in an exercise program.