32 paediatric patients requiring myelography were studied with iohexol 210 mgI/ml (n = 15) and iohexol 180 mgI/ml (n = 17). Visualization was good or excellent in over 90% of the group receiving the higher concentration and in over 83% of the lower. There were no side effects in either group and vital signs were not significantly altered during the procedure. In the majority of patients (14/18) who had CT, additional diagnostic information was obtained. Iohexol 180 mgI/ml is preferred for routine use, but 210 mgI/ml may give superior visualization with no apparent added risk. Procedural technique and good communication with the patients and their families may have contributed to the absence of side effects.