AbstractLong-term trials (1969-1978) on sandy loam were carried out with the raspberry cv. Malling Jewel. The plots received a single irrigation at pink-fruit stage, or they were irrigated whenever soil moisture tension reached 0.4 bar at a depth of 20-25 cm (limited deficit irrigation) or they were not irrigated (control). Vegetative growth was increased by limiting the soil moisture deficits experienced during the growing season and, although increases in yield were associated with greater amounts of fruiting-cane, the potential increases were not fully realized. The shortfall was partly due to a reduction in the number of fruiting laterals produced on the cane which was retained for fruiting. It is suggested that changes in management practice might eliminate this loss. Although berry size is a function of soil moisture deficit, single applications of water at pink-fruit stage did not increase yield because the scope for increase in berry size just before harvest was limited and because of the small effect that one application had at a time of high evaporative demand.