Soaps of monohydroxystearic acid, prepared by sulfation of oleic acid followed by hydrolysis, have been evaluated in syndet compositions. They can be used to replace a substantial proportion of the synthetic surfactant in both liquid and solid detergent compositions without loss of detergent efficiency or foaming properties. In contrast, sodium stearate and sodium oleate adversely affect performance. Compatibility is improved when these hydroxystearate soaps are incorporated in built liquid compositions. Since these materials exhibit the usual response of soaps to pH change and to divalent cations, there is complete assurance that they will be inactivated in ground water as well as in sewage treatment plants.