As one of the important odour sources, landfill sites have drawn more and more public attentions. Odour emissions from landfill sites depend on the waste buried, operation activities, running conditions, etc. A study for finding out all possible odorous compounds from a landfill was conducted by analysing of on-site gas phase samples and emission samples from a landfill leachate in Sydney, Australia using thermal desorber – gas chromatography – mass spectrometer (TD-GC-MS) and air server – thermal desorber – gas chromatography – sulfur chemiluminoscence detector (AS-TD-GC-SCD). 49 odorants were identified from gas emission samples collected from landfill leachate collection pipes and only 8 odorants were detected from flux hood emission samples of the collected leachate sample. This indicates that more sampling and measurement techniques are always better to acquire all possible pollutants from an unknown odour source. The contributions of these odorants to overall odour emissions were also calculated based on their concentrations and odour thresholds. The top 10 odorants from leachate transportation pipe include methyl mercaptan, ethyl mercaptan, m-xylene, H₂S, CS₂, 1,2,3,4-tetra-methylbenzene, p-xylene, 1,2,4-trimethylbenzene, ethylbenzene and α-pinene. They contributed more than 95% to the odour in the gas accumulated in the leachate collection pipe.