This research was carried out to determine the influence of landfill design and operating conditions on organic loading from leachate of municipal solid waste landfill operating in the tropics. Several factors were investigated including waste composition, compaction density, rainfall intensity, leachate re-circulation and accumulation of leachate in the waste cell. Laboratory scale lysimeters filled with urban wastes in Thailand were used to represent typical landfill conditions in Asian developing countries. Tropical condition was simulated by adding rainwater to the lysimeters where the precipitation rate was varied between 35 and 100% of maximum rainfall intensity. The collected leachate samples were determined for chemical characteristics. Leachate re-circulation was practiced to investigate incremental leaching of pollutants along the waste depth. Other lysimeters were operated with internal storage (saturation) condition. The experimental results revealed that the organic pollutant load increased with increasing rainfall intensity and substantially decreased from low compaction density (220 kg/m³) in open dumping to high compaction density (450 kg/m³) in sanitary landfill condition. Total organic pollutant load in water storage condition was considerably higher than conventional operation, but it was completely retained within the waste cell.