We report 3 cases of accidental intrathecal vincristine administration. All 3 patients died between 8 and 18 days after the incident because of decerebration. In the literature, we found 41 cases of accidental intrathecal injection of vincristine. These reports represent only a fraction of the existing problem. New in our report is the fact that the first 2 cases were attributed to viral infection, only after the detection of high levels of vincristine in the cerebrospinal fluid was the real cause of death ascertained. The third case occurred during the implementation of rules by the Dutch Childhood Oncology Group on how to handle intrathecal triple therapy; and despite sequential safety measures, the accident still occurred. In the Netherlands no more accidents of this nature have occurred in children after the introduction of a quadruple syringe system 8 years ago. In our opinion the best fail-safe solution would be the development of a unique connection that is incompatible with a standard Luer syringe.