A probability strength analysis of an unidirectional three-component hybrid composite (HC) is carried out for the cases of high modulus (HM) fibres and low modulus (LM) elastic fibers regularly embedded in a low elastic modulus matrix. Both single layer intraply and multilayer HC are considered. The fiber strength is assumed to be a random variable with a Weibull distribution. Breaking of the HM fibers are accumulated initially while probability of LM fiber failure is low. Failure modes tend to be covered by the two extreme cases of alternative failure of HM and LM fibers only. These modes can be categorized by using graph technique. Developed are the algorithm for finding the most probable pattern of fiber breaking and method for estimating the strength and fiber damage of a HC. The stress level at which the LM fibers are found to break represents a lower bound of the HC strength. Damage of HM fibers in a three-component HC is much higher than in a two-component HM fibre composite. Negative 'hybrid effect' for strength is obtained. © 1987.