The present invention provides mutant lipases which retain lipase activity, but have improved surfactant resistance and are thus highly advantageous for use in detergent compositions. Preferred lipases of this type include modified functional forms of a lipase of Pseudomonas alcaligenes having one or more amino acid substituents at or near the surface which effect interaction of the hydrophobic portions of surfactant molecules with initiation sites on the enzyme for surfactant denaturation.