In this study, the tension-tension fatigue response of bidirectional woven E-glass fibre reinforced unsaturated polyester composites was experimentally determined. The composite parts were produced via continuous laminating process. The probabilistic fatigue life distribution of the produced composites at various constant stress levels was then modelled, based on the two-parameter Weibull approach. A variety of different methods including graphical, method of moments and the maximum likelihood were conducted to predict the Weibull parameters. For the sake of reliability, the composite fatigue life data gathered at each constant stress level were correlated with the approvals of Kolmogorov-Smirnow goodness-of-fit test. Furthermore, the two parameter Weibull approach was utilized to relate the composite failure probability to the number of fatigue cycles that the composite withstands under a given load. As a result, the two-parameter Weibull approach has proved to be an efficient statistical tool to assess the reliability of polymer composite structures.