Four cultivars of winter barley (Hordeum vulgare L.) and two cultivars of combining pea (Pisum sativum L.) were grown in the field in the UK (52°N) and irradiated under banks of UV-B lamps in 1994/95 (barley) and 1996 (pea). Supplementary UV-B radiation was applied to treated plots as a proportional addition to the UV-B dose received under a control plot. Treated plants received a UV-B enhancement simulating the consequence of a 15% reduction in the amount of stratospheric ozone. No significant effect on yield and few significant effects on growth, pigment composition or chlorophyll fluorescence variables were detected. However, interplot variability was such that yield differences of <8·5% (pea) and <21·6% (barley) had less than a 95% probability of being detected as significant at the 5% level. The results indicate that yields of pea, and probably barley, would not be markedly affected by the increase in UV-B associated with a 15% reduction in stratospheric ozone. However, given uncertainties, such as the possible interactions between the effects of UV-B and those of other environmental factors, the possibility of significant crop responses to stratospheric ozone depletion cannot be excluded.