This paper is an analytical study of tooth failure in gearing having small numbers of teeth. For the analysis@ tooth contact stresses and combined shear stresses are investigated. The study is based on gear tooth loading@ accounting for load variations with time and other gear parameters in various phases of tooth meshing. The contact and shear stresses are by simultaneous: (a) contact stresses together with (b) stresses caused by the pinion and gear sliding. While developed for use in gearing with low numbers of teeth@ the method can be used for computation of stresses in gearing having more teeth. The results of the research could be used with AGMA 908-B89 for gears having less than 12 teeth.