Cadmium (Cd) is a heavy metal which is one of the most serious environmental pollutants. Exposure pathways include contaminated water, food and air pollution. Controversial results of Cd effect on immune response have been shown and its potential immunosuppressive action is still a subject of study. We investigated Cd effect in different concentrations on human peripheral lymphocytes proliferation and reactive oxygen species (ROS) production in neutrophils. Cadmium caused significant lower lymphocytes proliferation rate and decrease of ROS production in high concentrations (100 µM). Our and other works indicate that cadmium effect on immune response cannot be excluded and might widely differ in human population.