Cadmium transfer through and the retention of metal in perfused gills from rainbow trout ( Salmo gairdneri) has been studied in the presence of two detergents, LAS (linear alkylaryl sulphonate) and NP-10EO (nonylphenol ethoxylate). Accordingly, the effects of the metal and the surfactants on gill viability (vascular resistance, oxygen diffusion capacity, sodium net flux) was measured. Cd had no effect on gill viability either at 0.008 or at 9.0 μmol/liter during a 60-min perfusion period. The viability of the gills deteriorated markedly during 60 min of exposure to 100 μmol/liter LAS and to NP-10EO, or to a mixture of 100 μmol/liter surfactant + 8.1–8.3 μmol/liter Cd. LAS, 100 μmol/liter, reduced Cd transfer, whereas NP-10EO had no effect. NP-10EO increased Cd retention in gill tissue. LAS more than doubled Cd transfer through the gills when tested in concentrations expected to be found in a polluted recipient (0.9 μg/liter Cd + 0.05 mg/liter LAS). NP-10EO had no effect on the transfer when tested under these environmentally relevant conditions.