BACKGROUND: Obtaining intra-operative watertight closure of the dura is considered important in reducing post-operative cerebrospinal fluid (CSF) leak. The purpose of this study was to evaluate a fibrin sealant as an adjunct to sutured dural repair to obtain intra-operative watertight closure in cranial neurosurgery. METHODS: This randomized, controlled multicenter study compared a fibrin sealant (EVICEL® Fibrin Sealant [Human]) to sutured dural closure (Control). Subjects underwent supratentorial or posterior fossa procedures. Following primary dural repair by sutures, the closure was evaluated for intra-operative CSF leak by moderately increasing the intracranial pressure. If present, subjects were randomized to EVICEL® or additional sutures (2:1 ratio), stratified by surgical approach. Following treatment, subjects were successful if no CSF leaks were present during provocative challenge. Safety was assessed to 30 days post-surgery, including incidence of CSF leakage. RESULTS: One hundred and thirty-nine subjects were randomized: 89 to EVICEL® and 50 to Control. Intra-operative watertight closure was achieved in 92.1% EVICEL®-treated subjects versus 38.0% controls; a treatment difference of 54.1% (p < 0.001). The treatment differences in the supratentorial and posterior fossa strata were 49.1% and 75.7%, respectively (p < 0.001). The incidence of adverse events was similar between treatment groups. No deaths or unexpected serious adverse drug reactions were reported. CSF leakage within 30 days post-operatively was 2.2% and 2.0% in EVICEL® and control groups, respectively. In addition, 2 cases of CSF rhinorrhoea were observed in the EVICEL® group. Although not associated with the suture line where EVICEL® was applied, when combined with the other CSF leaks, the observed leak rate in the EVICEL® group was 4.5%. CONCLUSIONS: These results indicate that EVICEL® is effective as an adjunct to dural sutures to provide watertight closure of the dura mater in cranial surgery. The study confirmed the safety profile of EVICEL®.