Recently, we have been attempting to develop the dispersants for the improved dispersion of the asphaltenes that presented in heavy crude oil and became gel or precipitated upon the agglomeration. It has been known that effective dispersants for asphaltenes in heavy crude oil should have the following factors: a proper amounts of aromatic and functional groups that can interact with those of the asphaltenes, low molecular weight (MW < 10,000) because of the better solubility to heavy crude oil, amphiphilicity for the improved dispersion because the asphaltenes have both polar and non-polar units, and alkyl chains of proper lengths for the better miscibility with heavy crude oil. Thus, in the course of the present work, we prepared two types of dispersants, analyzed their chemical structures, and determined the effects of the dispersants on the dispersion of the asphaltenes. The two types of the dispersants were low MW styrene copolymers and various aliphatic alcohol, carboxylic acid, or amine compounds. In the first part of the work, we compared the effects of the types of the functional groups of the oligomeric styrene copolymers on the asphaltene dispersion. It was found that the sulfonic acid groups were better than the carboxylic acid groups on the dispersion. In addition, it was also observed that the more carboxylic acids groups in the acidic unit enhanced the dispersion. Furthermore, as expected, with decreasing MW of oligomers, the dispersion behavior of the asphaltenes became more improved. In the second part of the work, we investigated the effects of the addition of the aliphatic alcohols on the asphaltene dispersion. It was found that when the types of functional groups and alkyl chain lengths of aliphatic compounds did not affect the asphaltene dispersion in the heavy oil significantly. However, it was observed that the addition of NaOH to the heavy oil containing aliphatic alcohol or carboxylic acid compounds enhanced the dispersion of asphaltenes strongly. Interestingly enough, even the addition of NaOH to the heavy oil also improved the asphaltene dispersion, at least to some extent. Furthermore, it was seen that the effect of the NaOH addition to the heavy oil containing aliphatic alcohols became more pronounced than that to the heavy oil containing aliphatic carboxylic acids. Especially, the NaOH addition improved the asphaltene dispersion more significantly in the heavy oil containing 2-ethylhexyl alcohol than normal alcohols, having shorter or longer alkyl chains. Thus, we have been trying to find the reason why the base, i.e. NaOH, influences the asphaltene dispersion; we will present our interpretation on the results.