Paediatric age is a crucial time for bone mass accrual. Every deterioration of bone status in this period of life can affect the condition of the skeleton in the future. The awareness of primary and secondary disorders affecting bone health is vital for the identification of children at risk of developing osteoporosis. Among currently available methods of measuring bone mineral density in children, dual energy X-ray absorptiometry (DXA) remains the method of choice. However, the interpretation of a paediatric DXA report is complicated, which can lead to a misdiagnosis. Unlike in adults, the result is given in the Z-score; the T-score should not be taken into account. The preferred sites of measurement are the total body less head, and the lumbar spine. The current recommendations for bone mineral density assessment are provided by the International Society for Densitometry.