The primary purpose of this study is to investigate the anisotropic behavior of different glass-fabric-reinforced polyester composites. Two commonly used types of traditional glass fabrics, woven roving fabric and chopped strand mat, have been used. Composite laminates have been manufactured by the vacuum infusion of polyester resin into the fabrics. The effects of geometric variables on the composite structural integrity and strength are illustrated. Hence, tensile and three-point-bending flexural tests have been conducted at different off-axial angles (0, 45, and 90 degrees) with respect to the longitudinal direction. In this study, an important practical problem with fibrous composites, the interlaminar shear strength as measured in short-beam shear tests, is discussed. The most significant result deduced from this investigation is the strong correlation between the changes in the interlaminar shear strength values and fiber orientation angle in the case of woven fabric laminates. Extensive photographs of fractured tensile specimens resulting from a variety of uniaxial loading conditions are presented. Another aim of this work is to investigate the interaction between the glass fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, are interpreted in an attempt to explain the interaction between the glass fiber and polyester. (c) 2007 Wiley Periodicals, Inc.