It is shown that the urine from workers exposed to mercury vapor contains practically only inorganic mercury (II), which can be easily determined by flow injection cold vapor atomic absorption spectrometry after adding only HNO3to the urine at room temperature. If organic mercury is suspected to be present, the sample is treated with KMnO4/H2SO4at 80°C - 100°C and total mercury is determined. On using HNO3only, 30 - 40 urine samples/h can be easily processed. The method presents good accuracy, precision and high sensitivity, achieving a limit of detection and a limit of quantification (L.O.Q), respectively, of 0.12 mg/L and 0.4 mg/L Hg (II) in the final dilution, using 1.0 mL urine. Urine reference SRM - NIST as well as samples from workers exposed to mercury vapor were analyzed by the proposed methodology.