We determined the frequency of presumptive iron deficiency and lead toxicity in 198 Utah migrant children, ages 9-72 months, during the summer of 1985. There were no confirmed cases of lead toxicity. Thirteen per cent of those tested and 30 per cent of the children ages 9-23 months were iron deficient. Hematocrit determinations accurately predicted iron deficiency in only 35 per cent of the children confirmed to have this disorder via erythrocyte protoporphyrin screening. (Am J Public Health 1989; 79:631-633.) [ABSTRACT FROM AUTHOR]