The paper presents the probability analysis for the tensile strength of a unidirectional hybrid composite, consisting of elastic high modulus (HM) fibres and elastic low modulus (LM) fibres of equal amount embedded in an elastic low modulus matrix. Both single layer and laminated hybrid composites are considered. It is shown, that at the beginning of failure the HM fibre breaks are acciimulated. Various fracture modes may occur between the two extreme cases: a) alternately HM fibres and LM fibres break; b) only HM fibres break. The stress level at which the overstressed LM fibres are expected to break represents a lower bound on the hybrid composite strength. The damage level of HM fibres in hybrid composite is much higher than the damage level of HM fibres in HM fibre composite. Hybrid effect for strength is negative. Proposed method of analysis is applied to cross-ply composite.