With increasing use of the endoscopic endonasal transsphenoidal approach, wider attention is being paid to treatment and prevention of its complications. The aim of this study was to determine whether lumbar drainage (LD) has been effective in preventing and treating postoperative cerebrospinal fluid (poCSF) leakage or in assisting in achieving tumor gross total removal (GTR). Retrospective analysis of purely endoscopic endonasal transsphenoidal cases at a single center between 2008 and 2017 was done. We studied intraoperative cerebrospinal fluid (ioCSF) and poCSF leakage rates, duration of hospitalization, and GTR rate of the lesions, comparing patients with and without LD. Among 811 endoscopic endonasal transsphenoidal procedures, LD was used in 38 cases. There was no statistically significant difference between patients with and without LD with regard to incidence of ioCSF leakage. A statistically significant difference was found in obese patients with LD, who had an apparently increased rate of poCSF leak. The length of stay of patients with LD was significantly longer than the control group without LD. The GTR rate was also higher in patients without LD. Use of LD is correlated with longer immobilization and hospitalization without providing statistically significant advantages in terms of prevention or treatment of ioCSF and/or poCSF in low-risk and high-risk patients. Moreover, LD was not helpful in achieving GTR of tumors. •LD is an invasive procedure with its own risks.•Its usefulness in transsphenoidal surgery is still debated.•Even if ioCSF leakage is detected, careful skull base reconstruction can be effective in preventing further complications.•Elevated body mass index is a risk factor for poCSF leakage; obese patients should be closely monitored postoperatively.•When poCSF leakage is evident, prompt reoperation is usually recommended.