Some authors have reported that the clinical and pathologic behaviour of aneurysmal bone cysts (ABCs) is more aggressive in younger patients and that younger patients have more tumour recurrence. The authors carried out a retrospective, multicentred paediatric population-based analysis of 21 patients (14 boys and seven girls), 5 years of age or younger, with primary ABCs. Only patients with a minimum follow-up of 2 years were included. The most common operation was curettage (14 cases). Methylprednisolone acetate injection was used in two cases (failure in the initial diagnosis before biopsy) with negative results. An Ethibloc (Ethnor Laboratories/Ethicon, Norderstedt, Germany) injection was employed in four cases. There were five recurrences. Three lesions recurred once, one lesion recurred three times and one recurred six times. These recurrences occurred in two cases after methylprednisolone acetate injection, after Ethibloc (Ethnor Laboratories/Ethicon) injection (one case) and, after curettage (two cases). ABCs in children, 5 years of age or younger, do not seem to be more aggressive than in older children. Curettage is a surgical procedure that can be used even in young children. Of course, recurrence is always possible but the recurrence rate is not unacceptable. More aggressive operative intervention does not appear to be indicated.