Altogether 156 children treated for Wilms' tumour (WT) between 1970 and 1998 were studied. Sixty-six children, selected only by their attendance at clinic, were carefully examined and the findings compared to those from a case note review of 90 children. Congenital abnormalities were present in 45% of the examined cohort, in 19% of the case notes review group and in 30% overall. Novel findings included the association of WT with Marshall Smith syndrome, developmental delay in 3 of 4 cases of WT (one bilateral) and 1 sibling from consanguineous Pakistani families and another sibling also had leukaemia. The possibility of rare DNA repair or cancer predisposing disorders among these 4 families requires further study. Careful examination and history taking of an unselected patient cohort revealed a higher than expected incidence of clinical abnormalities which may be overlooked if not specifically sought.