The objective of this study is to assess computed tomography (CT) changes, both volume estimates and subjective features, following preoperative chemotherapy for nephroblastoma (Wilms tumour) in patients treated on the United Kingdom Childrens Cancer Study Group Wilms Tumour Study-3 (UKW-3) protocol and to compare CT changes and histopathological classification. Twenty-one nephroblastomas in 15 patients treated on UKW-3 were included. All patients were examined by CT before and after preoperative chemotherapy treatment. CT images were reviewed (estimated volume change and subjectively assessed features). CT changes were compared to histopathological classification. Of the 21 tumours, all five high-risk tumours decreased in volume following chemotherapy (median 79%; range 37 to 91%). The sole low-risk tumour decreased in volume by 98%. Ten intermediate-risk tumours decreased in volume (median 72%; range 6 to 98%) and five intermediate-risk tumours increased (median +110%; range +11 to +164%). None of the five high-risk tumours, compared to 15/16 intermediate or low-risk tumours, became less dense and/or more homogeneous, or virtually disappeared, following chemotherapy. Volume change following chemotherapy did not relate to histopathological risk group. Changes in subjectively assessed qualitative CT features were more strongly related to histopathological risk group.