The size distributions of sulfur (S), vanadium (V), and nickel (Ni) compounds, in four Crude oils, two residues and their saturate, aromatic; resin, and asphaltene (SARA) fractiont were-determined using gel permeation chromatography (GPC) coupled to inductively coupled plasma high-resolution mass spectrometry (ICP HR MS). The results show trimodal distributions of V, Ni, and S compounds in the crude oils and residues. V and Ni compounds are present in both-resins, and asphaltenes. Trimodal distributions are clearly apparent in the resins but not apparent in the asphaltenes:, In the latter, the predominant compounds have a high molecular weight (HMW), even when the solution, of asphaltenes is diluted by 40000-fold. In the resins, compounds with a medium molecular weight (MMW) were, expected; however; HMW compounds were observed, indicating that nanoaggregates or large molecules exist in both the asphaltenes and resins. Low-molecular-weight (LMW) compounds are,predominantly present in the resins and do not represent more-than 22% of V and Ni present in crude oil. These compounds appear to have molecular weights similar to simple metalloporphyrins.