In the current study, effects of domoic acid on some marine bacteria were studied. Domoic acid is a neurotoxin which affects human and animals and by some marine microalgea. For this study, heterotrophic marine bacteria were isolated from Iskenderun Bay and Samandag shore. 19 Pseudomonas sp. strains, 15 Acinetobacter sp. strains, 5 Alteromonas sp. strains and 9 Vibrio sp. strains were identified. For inhibition tests, varing concentrations of domoic acid (0.5µgr.ml^-1 and 1 mgr.ml^-1) were tested. It was found that there is not any inhibition effect of domoic acid on the all bacteria with used concentrations. Stimulator effect was determined by getting growth curve from the bacteria cultures which was added varying concentrations of domoic acid. It was found that 2.5 µgr.ml^-1 and 5 µgr.ml^-1 domoic acid showed inducer effect on 1.6 Pseudomonas sp. strain and 4.4 Vibrio sp. strain growth. In this study, it was also investigated the effect of domoic acid on heavy metal tolerance of these bacteria. The results of these study will contribute novel information on the effect of domoic acid on marine bacteria.