Abstract: By means of Cytokinesis-blocking(CB) method, a study was performed to detect the form ation of micro nuclei in cultrued human lymphocytes induced by four metal compounds. The result showed that nickle chloride, lead acetate, cadium sulphated and potssium dichromate could induce a significant increase in micro nucleus production after a continuous 24h exposureto various concentr ations of metal compounds. It is suggested that these metal compounds have mutagenic activity in human genetic material in certain doses.