This paper describes the changes of the acid phosphatases (AcP) and cathepsin activities throughout the cuttlefish embryo development. The enzyme activity kinetics appeared to be linked with the respective developmental stage. Activities of both enzymes increased during the last days of development suggesting a de novo production of these proteins by the maturing embryo in the digestive gland. The effects of selected heavy metals, i.e. Ag (0.06, 1.2, 60, 1200 ng.l-1), Cd (31, 61, 305, 610 ng.l-1) and Cu (0.23, 2.3, 23, 230 µg.l-1), were assessed on the AcP and cathepsin activities at the end of embryonic development and on the hatchling's weight. Enzymatic activities were not impacted by Ag and were significantly inhibited by the four Cd concentrations for AcP and at 610 ng.l-1 for cathepsin. Cu stimulated AcP activity at 2.3 µg.l-1. No cause-consequence relationship was found between metal effect on the enzymatic activities and the reduction of hatchling weight, suggesting that heavy metals could affect other physiological functions during embryogenesis.