Grease compositions comprising (A) a specific polyoxypropylene glycol monoether as the lubricating base oil and (B) a specific gelling agent as the thickening agent, consisting of at least one diurea compound represented by the formula ##STR1## wherein R.sub.1 is a divalent aromatic hydrocarbon radical, and R.sub.2 and R.sub.3 a cyclohexyl group, a cyclohexyl derivative group having 7-12 carbon atoms, or an alkyl group having 8-20 carbon atoms.