Disclosed is an oil soluble polyester composition, suitable for use as a dispersant in lubricating oils. The oil soluble polyester composition is prepared by reacting (a) a hydrocarbyl -substituted succinic acylating agent and (b) a di- hydroxyalkyl-substituted tertiary amine compound selected from a N,N'-di- hydroxyalkyl-substituted tertiary monoamine and a N,N'-di-hydroxyalkyl-substituted tertiary diamine.