Abstract The acute toxicity by single or combinations of copper and lead to the marine shrimp Palaemon adspersus Rathke, 1837 (Decapoda: Natantia) was evalulated by static bioassays, calculating the LT50 (lethal time for 50%) and the LC50 (lethal concentration for 50%). Each bioassay lasted up to 30 days and survival time has decreased with increasing concentrations of copper and lead in the environment. Copper was 4.25 times more toxic to Palaemon than lead. When tested in combinations of paired metals, the expected mortalities were not similar to those observed mortalities which suggested that paired metals acted interactively. Toxicities of mixtures of copper and lead were assessed also using the toxic-unit concept. The results of this study were compared with the other studies and discussed.