At the turn of the last century, rickets (vitamin D deficiency) was one of the most common musculoskeletal diseases of the paediatric population presenting to physicians. Today, the most common referral pathway for these patients ends in a paediatric orthopaedic outpatient clinic. Vitamin D deficiency is a clinical entity that can affect all children and should be looked for in all children with musculoskeletal symptoms.The child at risk of rickets is now white, breastfed, protected from the sun and obese. Vitamin D deficiency can present as atypical muscular pain, pathological fractures or slipped upper femoral epiphysis. Obesity is linked with lower vitamin D levels; however, in the paediatric population, this does not necessarily equal clinical disorder. Vitamin D supplements can be used to reduce the risk of pathological fractures in the cerebral palsy child. It should also form part of the differential diagnosis in the work-up of nonaccidental injuries. Children with a low vitamin D present with a higher incidence of fractures from normal activities. Vitamin D levels need to be assessed before any form of orthopaedic surgery, as it can affect growth, both in the diaphysis of the bone and in the growth plate.Vitamin D levels are a key element in the successful practice of paediatric orthopaedics. It is not just the possible cause of disorder presenting to the clinician but also extremely important in ensuring the successful postoperative recovery of the patient.