Luffa cylindrica of Turkey's Aegean Region was evaluated in terms of fiber characterization and the mechanical properties of its composite with polyester. Characterization of Luffa cylindrica was carried out by Fourier transform infrared spectrophotometer, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and thermogravimetric analysis. Cellulose, hemicellulose, and lignin contents of Luffa cylindirica were also determined. Deconvolutions of XPS data enable determining the distributions of functional groups on the surface of Luffa cylindrica. Luffa cylindrica-reinforced polyester composite was subjected to water aging under a steam of sea-water containing 5% sodium chloride for 170 h at 50 degrees C. After water aging, tensile strength, flexural strength, interlaminar shear strength, and tensile elongation at break values of the composite decreased similar to 28%, 24%, 45%, and 31%, respectively. However, tensile modulus and flexural modulus did not change significantly. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2330-2337, 2012