The determination of toxic metals in urine is an important clinical screening procedure. In this study, the aim of our investigation was to determine the concentrations of Pb, Cd, and Ni in urine samples under routine clinical laboratory conditions. To assess the reliability of these methods, critical factors such as detection limit(s), calibration range(s), cost, accuracy and precision were studied. The method was employed for the quantitative determination of lead, cadmium and nickel in urine samples from steel production and quality control (QC) workers and healthy unexposed controls. After pre-treatment with acids, the samples were digested via a microwave oven and the samples were determined by a graphite furnace atomic absorption spectrometry (GFAAS). Quality control for these procedures was established with the concurrent analysis of Standard Trace Metals 7879 Level II and NIST SRM 2670 (Toxic Elements in Freeze Dried Urine). The results indicate that urinary lead, cadmium and nickel levels of the exposed workers are significantly higher those of the controls. The possible connection of these elements with the etiology of disease is discussed. The results also show the need for immediate improvements in workplace ventilation and industrial hygiene practices.