The postweaning growth and carcase characters of steers and the maternal performance of heifers from a complete two-breed diallel of the Devon and Hereford breeds were examined under Australian temperate grazing conditions. The aim of the project was to estimate additive and non-additive between breed differences for direct and maternal effects.The experiment reported here forms part of a large, long-term crossbreeding trial initiated in 1983 by the Devon Cattle Breeders' Society of Australia. Phase 1 of the trial evaluated the preweaning performance of Devon, Hereford and reciprocal cross calves generated from the complete diallel design and reported by Gyles (1987). This project reports Phase 2 of the trial which has examined growth postweaning in two different nutritional environments and carcase characteristics of 110 steers. Also the maternal performance (calf growth, milk and suckling and grazing behaviour) of 112 heifers was examined. The steers and heifers consisted of four breedtypes produced from the base mating of Devon and Hereford females to 15 Devon and 14 Hereford sires.