This study investigated whether the addition of 25 mu g intrathecal fentanyl to levobupivacaine spinal anaesthesia for outpatient inguinal herniorrhaphy allows a sub-anaesthetic levobupivacaine dose to be used. Forty patients were assigned to receive 5 mg levobupivacaine 0.5% mixed with 25 mu g fentanyl (group LF) or 7.5 mg levobupivacaine 0.5% (group L). The highest sensory block levels achieved were T7 (range T5 - T9) and T6 (range T4 - T9) in groups LF and L, respectively. The times to two-segment regression, S2 regression, ambulation, urination and discharge were all significantly shorter in group LF than group L. These results indicate that, for outpatient inguinal herniorrhaphy, intrathecal fentanyl combined with low-dose levobupivacaine provides good quality spinal anaesthesia and minimizes the need for intra-operative analgesia. This protocol is well suited for the outpatient setting because it features rapid recovery of full motor power, sensory function and bladder function.