This paper presents results from a study of the influence of surface preparation on the mechanical performance of overlaminated polyester composites. Panels of 16 woven glass plies have been prepared in two halves by hand lay-up. After the first 8 plies were laminated the surface was either protected by a peel ply or left in air. The overlamination of the second half of the composite thickness was completed after different periods and interlaminar shear, flexure and mode I fracture specimens were tested. The results enabled the influence of the delay and the surface condition to be related to mechanical performance. Surfaces protected with peel plies show very low G(Ic) propagation energy release rates. Results are compared to those from continuous lamination of the 16 ply composite. Interlaminar fracture tests are shown to be much more sensitive to overlamination conditions than the traditional short beam shear test. Results are interpreted in terms of fracture surface features.