The results from the characterization of solubility separated fractions of the Maya crude oil were studied. A detailed analysis was performed on fractions produced using separation in heptane and NMP. The aims of the work were two-fold. The first was the characterisation of the Maya crude-oil and its maltene and asphaltene sub-fractions in terms of mass distribution and structural make-up. The second was to validate the analytical techniques and methods used in this characterisation. The methods employed were primarily developed using coal-derived samples with appropriate modifications made for the analysis of petroleum-derived materials. The Maya crude-oil was examined by four main techniques: Size Exclusion Chromatography (SEC), Laser Desorption-Mass Spectrometer (LD-MS), Ultra Violet-Fluorescence (UV-F) and Nuclear Magnetic Analysis (NMR). SEC and LD-MS were used to arrive at estimates of the mass distributions. UV-F and NMR spectroscopy were used to investigate structural features of the samples.