Abstract: When fiber reinforced composite materials are used forengineering structures and components, they are often subjected to complexservice loading conditions, involving multi-axial stress. For the reliable operation and efficient design ofthese engineering structures, therefore, it is important to assess the materialbehaviour and develop a reasonable life prediction model under multiaxialstress conditions. Firstly, uniaxial fatigue theories and life predictionmodels of fiber reinforced composite materials are briefly reviewed.Secondly, based on the author's research work on multiaxial fatigue ofcomposites, fatigue failure criteria and models for fatigue life predictionare discussed and merits and defects of different types of criteria andmodels are also analyzed. Some suggestions are made for future studieson multiaxialfatigue on composites. Finally, multiaxial fatigueexperimental methods on composites and some of their difficulties aresummarized.