The recovery of alpha-phenylglycine from diluted aqueous solutions by micellar extractive ultrafiltration (MEUF) was investigated using several surfactants as extraction agents: cetyl trimethyl ammonium bromide (CTAB, cationic), sodium dodecyl benzene sulfonate (SDBS, anionic), polyoxyethylene-sorbitan mono-oleate (Tween 80, non-ionic) and lauryl sulfobetaine (SB3-12, amphoteric). Preliminary centrifugal ultrafiltration experiments were carried out at different pH conditions, and at various amino acid and surfactant concentrations, using Millipore Ultrafree-4 units of 5, 10 and 30 kDa polyethersulfone membranes. Experimental results show that similar amino acid extraction yields were obtained with the ionic surfactants, and the extraction was negligible when non-ionic and amphoteric surfactants were used. Best results were obtained using the 5 kDa membrane for an aqueous system with 1000 mg L-1 of alpha-phenylglycine at pH = 11.2 and at CTAB concentrations higher than 50 mM. Crossflow ultrafiltration experiments were carried out using a tubular ceramic zirconia membrane of 20 nm pore size, under different process conditions and operation modes. More than 90% of CTAB rejection and 85% of alpha-phenylglycine extraction were achieved for the MEUF of a CTAB (80 mM) -water-alpha-phenylglycine (1000 mg L-1) system, with permeate fluxes higher than 70 kg m(-2) h(-1) after 8 h of operation time.