Model amino acids, DL-phenylatanine, glycin, and L-4-hydroxyproline, were extd. from 1-7 mM solns., with 2.5% of a nonionic, oxyethylenated(n = 7 or 10)methyl dodecanoate or polyoxyethylene(9) nonylphenyl ether. The 0.004 M acids were sepd. (with centrifugation) in resp. 60, 58, and 52% into the water phase. The 10 and the 9 were the most and the least efficient surfactants, resp. The 7 was next best; it gave lower cloud ps. than did the 10. Cloud ps. were detd. in relation to surfactant concn., amino acid concn., and NaSCN and NaCl as salting-in and salting-out agent, resp. optimum heating time was 4 hrs.