Problem Statement: Landfill leachate had been implicated in environmental pollution, developmental anomalies, birth defect and surface and groundwater pollution worldwide. This study has been conducted to determine the toxicity of landfill leachate from three different landfills in Malaysia on fry common carp (Cyprinus carpio L., 1758; Pisces, Cyprinidae) in combination with some physico-chemical parameters analysis. Approach: Leachates were collected from Air Hitam (AHL), Ampar Tenang (ATL) and Sungai Sedu (SSL) landfills. The experiments were performed as three replicates using a total of 180 carps for each definitive test. The semi-static renewal method of acute toxicity test was used. The data obtained were statically evaluated by the use of the EPA computer program based on Finney's Probit Analysis Method. Results: The leachate used in this study had an invariable of (1640-7600 mg L −1 ) COD and (321.22-956.86 mg L −1 ) Ammonical-N. The 96 h LC 50 values of landfills leachate from the three landfills using fry C. carpio individuals with an average weight of 0.92±0.24 g and average length of 3.83±0.19 cm were found to be 1.132, 2.0 and 3.822% respectively. Among the behavioral changes observed for the individual fish at different leachate concentrations, decline in general activity, loss of balance, breathing difficulties, excessive mucosal secretion and gathering at the surface for breathing. Conclusion: This study of acute toxicity to the recommended fish species, C. caprio, is considered the first in Malaysia. Further research with toxicity testing methods directly on fish will be very useful in assessing possible ecological risk assessment of landfill leachate.