Crambe (Crambe abyssinica Hochst. ex Fries) is an annual cruciferous oilseed crop with a high content of erucic acid (55-60%) in the seed oil. Since 1990, a breeding programme in crambe has been carried out at the DLO-Centre for Plant Breeding and Reproduction Research. Three accessions, two early flowering American breeding lines and a late flowering European land race, were used in a crossing programme. Five generations were raised. From the F3 generation onwards selection was performed for agronomical characteristics. Estimation of broad-sense heritability values on the basis of variation between F3 lines revealed high values for thousand seed weight, moderate for plant height, earliness and seed oil content and low for seed yield and number of seeds produced per square metre. In comparison to the reference populations, only limited progress in seed yield was obtained by selection. Improvement of seed yield performance was also observed in the reference populations after growth of the subsequent generations. It was concluded that for Dutch environmental conditions, selection for earliness might be an effective tool to improve the total yield of seed oil. This conclusion was confirmed by the selection of early flowering lines with a high seed oil content and an improved fatty acid composition.