Extensive cockle culture on coastal intertidal mudflats which function as productive feeding grounds for fish and shrimp may affect mudflat productivity and disturb feeding activity. The aim of the present study is to examine fish ingressions into two adjacent coastal mudflat areas, one with cockle culture and the other without cockle culture, especially to compare their diversity and abundance. Two sampling sites were selected at Bagan Sungai Buloh (BSB: with cockle bed) and BaganPasir (BP: without cockle bed) in the Kuala Selangor mudflat area. Monthly samplings were carried out on spring tide using an enclosure trap (belat lengkung). In six months of samplings, 63 identified species of fishes and eight species of prawns were recorded. Both mudflats differed in their fish species richness, with 59 species in BSB and 41 species in BP. However, the BP mudflat had significantly higher fish biomass (142.2 ±148.7 kg/ha) than BSB mudflat (43.6 ±41.2 kg/ha) (t-test, p<0.05). As for mean fish abundance, the difference between two sites is not significant. Most frequent fish species that regularly occurred every month on both sites were the grey mullet Liza subviridis and tongue sole Cynoglossus bilineatus. There was no significant difference in penaeid shrimp abundance and biomass between both sites. The dominant species of shrimps in term of biomass in BSB was Fenneropenaeus merguiensis, whilefor BP was Metapenaeus affinis. Low abundance and biomass of fish species in cockle culture area are likely due to direct disturbance from culture activity as well as continually scoured sediments from cockle harvests which may affect mudflat productivity.