Asphaltene onset concentration and bulk deposition were measured for a typical live reservoir oil titrated withn-C6H14,n-C5H12,n-C4H10, C3H8, C2H6, CH4and CO2at 100° C (212 ° F) and 29.9 MPa (4340 psia). The concentration of titrant at asphaltene onset was observed to decrease approximately in a linear fashion with decreasing molecular weight of the paraffinic solvent; CH4did not induce any asphaltene precipitation. Bulk deposition experiments were performed using a solvent: oil volume ratio of 10:1; the results indicated that the weight percent of asphaltenes precipitated increased exponentially with decreasing molecular weight of the paraffinic solvents. More importantly, the asphaltene molecular weight showed a maximum forn-C4H10precipitated asphaltenes. Possible explanations for this unusual result are presented.