Gammarus aequicauda, collected at different times of the year was used to assess the mortality rates and the sensitivity to cadmium (96 h LC50), at different laboratory temperatures (10, 15, 20, 25 degrees C). The survival in 10 days sediment control test, was high at all tested temperatures, ranging from 4 +/- 1% at 10 degrees C (winter collection) to 13.3 +/- 2.1% at 25 degrees C (spring collection). The 96 h-LC50 values recorded, ranged from 1.50 mgCd/L in winter at 10 degrees C to 0.10 mgCd/L in spring and summer at 25 degrees C. The results showed that temperature and season of collection influenced mortality rates and G. aequicauda sensitivity to cadmium.