Mangroves play a significant ecological role as a physical habitat and nursery grounds for a wide variety of aquatic vertebrates and invertebrates include molluscs. This study focuses on assessing the diversity and characteristics of mollusc species in disturbed and undisturbed mangrove ecosystem areas in Delta Tumpat, Kelantan. In each site, molluscs were collected using dredging method during high tide and gleaning technique during low tide. Physical characteristics and diversity index (H’) were calculated for both sites. A total of 14 mollusc species were found in the study area including five species from Bivalvia and nine species from Gastropoda class. More species were found in the undisturbed area which had produced a high species diversity (H’= 1.99) compared to the disturbed area. The biggest species found at both areas was Telescopium telescopium with 7.62 cm in size. Meanwhile, Cerithedia aurisfelis was the smallest species found with the size of 0.87 cm. The difference in the growth of molluscs species in mangrove ecosystems depends on the quality and quantity of available food resources.