This study examined the determination of BOD in landfill leachates by dilution (D-method) and manometric methods (M-method). The differences in results were discussed based on statistical tests. The effects of sample dilution. seeding, chloride and total Kjeldahl nitrogen (TKN) level were examined. The M-method was found to be more sensitive to increases in chloride and TKN concentrations. However, in the M-method the positive interference of nitrogenous BOD (NBOD) to carbonaceous BOD (CBOD) was more successfully prevented. The BOD rate constant k and the ultimate BOD (BODu) were estimated by non-linear regression. with the M-method these parameters could be more reliably estimated than the D-method. Suggestions were made for BOD analyses in landfill leachates in future studies.