Five amphipathic polymer systems (strong and weak anionic, strong and weak cationic, and nonionic) were prepared by two techniques giving lower and higher molecular weights. The various polymer systems were characterized by Brookfield viscosity and foaming tendency in aqueous solution. These polymers were evaluated for efficiency in removing solids from unsettled raw sewage using three methods: a simple continuous flotation cell, a static pressurized water flotation unit, and a conventional jar test. The nonionic and anionic amphipathic polymers showed little or no flocculating ability; only the cationic types were effective. Qualitatively the strong cationic polymers (dimethylaminoethyl metharcrylate/ethyl bromide quaternary salt as comonomer) were more effective than the weak cationic polymers (dimethylaminoethyl methacrylate/HC1 salt as comonomer). Effectiveness increased with increasing % quaternary comonomer.