Previous work in this laboratory showed that concurrent consumption of an iron-deficient diet and exposure to lead caused seizure activity in Albany heterogeneous (HET) stock mice. In the present investigation, 26 Albany HET mice (ages 35 to 57 days of age) ate either an American Institute of Nutrition approved iron-sufficient (30 ppm) diet or an iron-deficient (less than 3 ppm) diet and drank either a 0.5% lead solution or distilled water for 12 weeks. We measured several activities in an open-field, hole-board apparatus, and spontaneous seizures which occurred during testing, changes in body weight, and hemoglobin levels. Replicating previous findings, mice fed the iron-deficient diet and treated with lead had more seizures with longer durations and longer postictal periods than animals given the iron-sufficient diet but also treated with lead. Mice not exposed to lead did not seize. Both lead-treated groups had lower rates of body-weight gain over the 3-mo. period and lower hemoglobin values than nonlead-treated animals. Changes in activity were observed in the open field as a function of diet and exposure to lead.