Laboratory experiments were carried out to study bioaccumulation and determine a concentration factor (CF) for technetium (95mTc) in the homarid crustacean Nephrops norvegicus L. The steady state CF for accumulation from seawater was estimated to be about 2,000 and the biological half-time was about 50 days. The highest tissue Tc concentrations were found in the green gland and the digestive gland. Depuration following accumulation from water was slow with a half-time of about 165 days. Tc accumulation from labelled food followed a biphasic model with one compartment containing about 94 percent of the ingested activity and with a half-time of about 1 day and the second compartment containing about 6 percent of the ingested activity with a half-time of about 56 days. Most retained activity was found in the digestive gland.