Bismuth is determined in blood and urine by means of atomic-absorption spectrophotometry following generation of bismuth hydride from a wet-oxidised sample. Recoveries are shown to be satisfactory, and the detection limit using analytical-reagent grade reagents is less than 0.01 µg ml–1. The direct determination of bismuth in urine by means of hydride generation has been investigated, and it is shown that there is severe suppression and poor recovery.