The identification of an abdominal mass in a child, either coincidental or symptomatic, may be due to a tumour. An abdominal tumour may present with life-threatening symptoms, requiring prompt assessment and management. Although the discovery of such a finding usually warrants inpatient transfer or outpatient referral to the tertiary oncology centre, the initial evaluation, management and communication with the family by the general paediatrician is crucial. A thorough history and examination, which includes an organised, structured approach to abdominal masses, is paramount. The anatomical location of the mass, age of the patient and the presence of any associated symptoms or signs must be considered together in order to formulate a list of potential differential diagnoses and guide the next appropriate investigations. This article aims to guide general paediatricians through the assessment and initial management of a child presenting with an abdominal mass suspected to be a tumour.