Carbonyl sulphide (COS) is the principal form of 35S in the coolant of CO2-cooled nuclear reactors under operational conditions. Measurements were made of the deposition velocity (Vg) of [35S]-COS (on a single-sided leaf area basis) to a range of vegetable cultivars under turbulent conditions simulating maximal deposition in the field. The Vg for all the cultivars was (75% of the Vg to perennial ryegrass (Lolium perenne L.) at 7.75 x 10-4 m.s-1. Uptake was greatest for brassicas and radishes (mean Vg 4.60-5.79 x 10-4 m.s-1) and least for lettuces, onions and spinach (mean Vg 2.48-3.96 x 10-4 m.s-1). Under illuminated conditions, when the stomata are open, differences in stomatal resistance accounted for -3, about seven times ambient) had no effect on the stomata. The results show that the use of Vg values of [35S]-COS to ryegrass in models to estimate ingested radiation dose following the consumption of green vegetables would increase the margin of safety by overestimating the 35S content of the crop by 30-300%.