Although workers may be exposed to chromium metal, Cr(III) compounds, and Cr(VI) compounds at the workplace, only Cr(VI) compounds are of primary concern in terms of possible health hazards. A special health surveillance program must focus on known health impairments and target organs. Medical surveillance in combination with biological monitoring can help to protect the workers' health. Biological monitoring for chromium exposure in urine, blood, and erythrocytes provides different types of information. Whereas chromium measurement in urine and whole blood or plasma is indicative of recent total chromium exposure, chromium detection in erythrocytes is attributable to Cr(VI) only and covers retrospectively a longer period of time due to the erythrocyte life span. Possibilities of biological effect monitoring are discussed.