The aim of the presented work was to elucidate whether supplementation with zinc affects the immunological response in BALB/c mice. Zinc was used as ZnCl2 in concentrations of 10(-4); 10(-5); 10(-6) M in PFC and migration-inhibition test. It was found that the numbers of anti-SRBC antibody-producing cells in mice injected with zinc were greater than in the control ones. This enhancement of PFC was proportional to the concentration of zinc. ZnCl2 itself inhibited target cell migration in concentration 10(-4) M but had no effect at 10(-5) and 10(-6) M. Zinc in all investigated concentrations promoted the action of suboptimal as well as optimal doses of PHA and enhanced target cell migration inhibition. It was determined that ZnCl2 in concentration 10(-4) M activated mouse lymphocytes for migration inhibitory factors production. We postulate that zinc may enhance the effectiveness of anti-infectious immunity.