Axial creep tests of a 10vol% boron-aluminum hot-pressed monolayer composite were carried out under several constant loads at 300°C in air. The composite exhibited slight primary creep, but did not show appreciable secondary creep. Several specimens experienced a momentary increase of strain during the creep test which separated the creep curve into two regions, because of individual fiber breakages in the composite. Then, almost all the specimens abruptly fractured without a tertiary creep. The creep-rupture surfaces consisted of relatively complicated paths with a few flat regions perpendicular to the fiber axis linked by longitudinal matrix shear fracture. From the viewpoint of materials reliability engineering, the statistical properties of the creep-rupture lifetime were investigated. The average lifetime decreased with an increase in the applied load, and the considerably large coefficients of variation were estimated in every case, being around 1000%. However, these scatters were estimated to be smaller than the scatter of the creep-rupture lifetime of the boron fiber itself. That is, such statistical relations between lifetime properties of the fiber and those of the composite are almost the same as those for tensile strength. Additionally, a stochastic model which predicts theoretically composite strength from fiber strength was developed for predicting the probability distribution curves of the creep-rupture lifetime. The predicted distribution curves agreed well with the experimental results under high applied load conditions.