The present study deals with the determination of the incidence of chromosome changes in workers at a factory making storage batteries in Baghdad city. Blood samples were collected from 19 workers and 9 employees of the Scientific Research Council as control individuals, and chromosomes prepared from lymphocyte cultures were analyzed by standardized methods. Statistical analysis of the results gave significantly higher frequencies of chromatid and chromosome aberrations, particularly gaps, among the workers. No significant differences were observed in the incidence of chromosome aberrations in cells of smokers and non-smokers in both lead-exposed workers and controls. Therefore the observed increase in these aberrations was found tobe associated mainly with exposure to lead oxides during the manufacture of the lead alloy grids and lead smelting.