Neutral red retention (NRR) assay was used to evaluate the effect of changes in water temperature on lysosomal membrane integrity in the hemolymph of blacklip abalone, Haliotis rubra. Results from gradual temperature changes between 7°C and 16°C and between 16°C and 25°C showed that water temperatures within the range of 15°C to 17°C were optimal for maintaining lysosomal membrane integrity in this species. The rapid temperature changes between the ranges used in the gradual temperature change experiments indicated that when abalone were transferred directly between these temperatures their NRR time gradually increased or decreased to the level corresponding with the new temperature. However, when abalone were transferred directly between 7°C and 25°C or between 11.5°C and 20.5°C their NRR times initially decreased significantly, and then gradually increased to the levels corresponding with the new temperatures, indicating that different ranges of water temperature change can affect the lysosomal membrane integrity differently. The NRR times of blacklip abalone at 7°C, 16°C and 25°C were 40.0 ± 2.89 min, 113.33 ± 3.85 min and 35.0 ± 2.89 min, respectively.