To provide a novel polysuccinimide composition which is derived from an acid derivative, a polyamine, and a polycarboxylic acid derivative, and is useful as a dispersant and an antiadhesive agent in a lubricant and a hydrocarbon fuel.

In a method for producing a polysuccinimide composition by reacting a mixture, the mixture comprises an acid derivative; a polycarboxylic acid derivative; and a polyamine selected from the group consisting of an alkenyl- or alkyl succinic acid derivative, a polymer of a primary unsaturated acidic medical agent and 1,1-disubstituted olefin, and a mixture thereof, and the reacting mixture contains from 4 to 40 wt.% of the polycarboxylic acid derivative, and the mixture contains from 0.1 to 1.5 equivalents of the polyamine per equivalent of acidic groups of the acid derivative + the acidic groups of the polycarboxylic acid derivative.