The bioconcentratlon and metabolism of picric acid and picramic acid were determined for rainbow trout. The bloconcentration factor (BCF) in the epaxlal muscle at 42 d for both of these compounds was less than 1; the skin had a BCF value of 1 and 9, respectively. The half‐life (t½> elimination for the high and low dose of picric acid was 12.0 and 12.5 d, respectively; and for picramic acid was 9.0 and 9.5 d, respectively. In separate experiments, approximately 34% of the injected [14C]plcric acid was metabolized to picramic acid, glucuronide conjugates, and an unidentified group of compounds, and 42% of the [14C]plcric acid was metabolized to picric acid, giucuronide conjugates, and an unidentified group of compounds. The low bioconcentration in the trout muscle may be due to the trout's ability to excrete the parent compound and metabolites. The higher radioactivity observed on the skin may be due to the water route of exposure and the binding of the parent compounds to protein.