Summary. Sediment formation or cloudiness in canola oil presents a problem for the industry which is currently solved by winterisation. Various techniques have been used to examine the chemical and physical properties of the sediment. Knowledge of the physical properties are due largely to investigations using differential scanning calorimetry. Chemical composition has been determined by high resolution chromatographic methods particularly gas chromatography following preliminary separation of the sediment from the oil and fractionation. Major components of the sediment are wax esters with lesser amounts of triacylglycerols, hydrocarbons, free fatty acids and alcohols. Nevertheless, full characterisation of the sediment is yet to be achieved although the full potential of developments such as softer ionisation techniques for mass spectrometric detection in high performance liquid chromatography have not been exploited. The process of sediment formation is discussed in relation to nucleation of the oil and crystal growth. On this basis, factors determining sedimentation behaviour in a particular sample are probably kinetic and influenced by trace components of the oil. The fundamental question to be answered in future work is the relative role of environment and genetics in regulating susceptibility to sedimentation.