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The synthesis of poly(y-stearyl L-glutamate) is reported, starting from glutamic acid. The y-stearyl L-glutamate amino acid (SLGAA) was prepared from stearyl alcohol and L-glutamic acid. Ring closure of SLGAA to the cyclic -carboxyanhydride (NCA) monomer was accomplished using bis-(trichloromethyl) carbonate (triphosgene). Polymerization of the SLGNCA monomer in the presence of either primary amines or sodium methoxide produced a series of polypeptides with molecular weights ranging from 20 000 to 300 000. The polydisperse polymers were characterized by static and dynamic light scattering, solution viscometry, and 13C NMR, and infrared spectroscopy. The polymer was also modeled using the SYBYL molecular graphics package. The combined data indicate a semiflexible structure, with PSLG side chains being well extended from the polymer backbone in the good solvent, tetrahydrofuran. Gel permeation chromatography and dynamic light scattering data indicated polydispersity ratios (MJMn) in the range of 1.1-2.0. The Mark-Houwink-Sakurada coefficients obtained were K = (1.26 ± 0.3) x 10-5 cm3/g and a = 1.29 ± 0.09 for Mw in the range of 38 000-250 000. The hydrodynamic diameter of the PSLG rod was calculated to be 3.7 ± 0.2 nm; the diameter of mutual exclusion calculated from the Zimm-Schulz-Onsager equation was 3.6 ± 0.7 nm. These values were in good agreement with the value obtained from the SYBYL molecular model.