Twenty-seven cutting needle biopsies were performed on 25 children with suspected malignancy using computed tomographic (CT, 22) or ultrasound (US, 5) guidance. Anatomical sites were: retroperitoneum 6, liver 4, kidney 4, abdomen/pelvis 4, thorax 4, bowel 2, neck 1. Sixteen patients (64%) underwent subsequent open biopsy (5), marrow biopsy (2) or resection (9). There was complete concordance between the histological findings from the open or marrow biopsy and the previous needle biopsy in 12 of these 16 patients; in two patients the needle biopsy was misleading, causing inappropriate initial treatment in one. In two other patients needle biopsy was correct but lacked specific diagnostic features. Needle biopsies were performed under general, local or Ketamine anaesthesia. There were no apparent complications related to these procedures. We believe that radiologically-guided cutting needle biopsy should replace open biopsy in most children with solid malignant lesions. It can easily be performed during a single anaesthetic episode which allows radiological evaluation, biopsy, bone marrow and cerebrospinal fluid sampling. However, the potential for sampling error and histological variation within these tumours needs to be borne in mind.