The effects of percutaneous Ethibloc (Ethicon/Johnson & Johnson, St-Stevens-Woluwe, Belgium) injection into primary aneurysmal bone cysts were analysed. Two patients with a venous drainage after injection of a medium contrast were excluded. Twelve patients underwent at least one percutaneous injection of Ethibloc. The average follow-up period was 5.1 years. At final follow-up, six patients had complete healing of the cyst, three had partial healing and three, who had no response, were treated by curettage and bone grafting. Complete healing was observed for all the aggressive lesions. No major complications were noted. Ethibloc injection may be performed as a primary treatment of aneurysmal bone cysts if the technique is followed with precision.