AbstractFruits of raspberries cv. Glen Prosen, EM 4997 (firm), Glen Clova and EM 5007 (soft) were assessed at different stages of development to quantify fruit firmness, rates of ethylene evolution and ripening rate. Penetrometry data confirmed suspected firmness differences. Firmness correlated with rates of ethylene evolution. Rates of ethylene production also correlated with receptacle size. Storage of green fruits in 20 ?l ethylene/litre reduced fruit firmness, increased respiration rate and colour (anthocyanin) development and stimulated the development of cell wall hydrolase activities. However, during natural ripening in the field, fruit respiration rate declined, which indicates a non-climacteric ripening pattern. In drupelets, the activities of polygalacturonase, pectin methylesterase, Cx-cellulase and β-galactosidase increased substantially as ripening progressed.