Purpose: This study evaluates the safety, efficacy, and indications for continuous lumbar drainage (CLD) in patients following endoscopic third ventriculostomy (ETV). Methods and results: We retrospectively reviewed the clinical data of 22 consecutive patients treated between 1996 and 2010 with CLD after ETV. The decision to insert a CLD was made in selected patients only. CLD was inserted in cases of high measured intracranial pressure (12 patients), clinical symptoms indicative of continuing hydrocephalus (2 patients), and "prophylactically" in 8 patients, based either on the clinical condition of patients before ETV or on technical difficulties during the ETV procedure, which seemed to increase the risk of ETV failure. CLD insertion took place either in the operating room immediately following the ETV procedure or under very specific conditions and with close patient monitoring in an ICU setting. Only four patients eventually required shunting, all within 1 month after ETV. Therefore, the overall ETV success rate was 81.8% (18/22 patients). Of the 14 patients suffering from measured or clinically observed continuing hydrocephalus, 12 (85%) ultimately recovered without the need for a permanent shunt. Without the CLD, some of these patients would probably have been declared "failures" and referred for a standard shunt. CLD provided a time window following ETV for the absorption system to recover and return to full functionality. Conclusions: Selective usage of CLD is a reasonable and safe method to gain time and possibly facilitates the recovery of absorption capacity following ETV. CLD should be considered before conceding a post-ETV patient as a failure. © 2011 Springer-Verlag.