The bismuth contents of various digested urine samples and prescription medicines were determined by atomic absorption spectrometry combined with hydride generation. The procedure followed was a standard addition method for urine and direct calibration for the prescription medicines. The detection limit of the method was determined to be 320 pg ml-1 Bi with an analytical frequency of 150 h-1. A relative standard deviation of 4.7% was found for Bi in urine at the level of 4.3 ng ml-1 Bi. Interference caused by NiII, CoII, CuII, AgI, SeIV, SbIII and HgII could be controlled with a masking solution of thiourea (0.2%)-KI (10%).1231717-9