Between 1960 and 1986, 177 cases of Wilms' tumour were reported to the New Zealand National Cancer Registry. There was an equal sex distribution and 93.2% of patients were in the paediatric age group with a mean age of 3.4 years. The mean symptom interval was 2.0 months and the majority of patients presented with localised disease, although the incidence of advanced disease was greater than that reported from other series. The 5-year survival rate for all cases was 52.5%. Data were divided into patients presenting before and after the publication of the first National Wilms' Tumour Study (NWTS) in the United States in 1976. In patients presenting after 1976 the diagnosis was based on histology in 100%, compared to 58.6% in patients before 1977. Treatment was considered curative in a greater proportion of the post-1976 group. Treatment modalities reflected the recommendations of the NWTS and the 5-year survival rate of this group was 78.3%, this being similar to that reported from the NWTS. Multivariate analysis showed patient age, symptom interval, tumour stage and treatment (pre- and post-NWTS) to be independent predictors of survival.