BACKGROUND: We postulated that loss of epidural negative pressure might affect on the sensory blockade level of spinal anesthesia. METHODS: Thirty nine patients were involved in our study; group 1, spinal anesthsia with 23G spinal needle (n=20): group 2, spinal anesthesia with 27G spinal needle through the 18G Weiss epidural needle (n=19). Sensory blockade level was checked by pinprick test at 5, 10, 15, 20, 25, 30, 40, 60 and 90 minutes after spinal anesthesia. RESULTS: There was no difference of sensory blockade level between group 1 and 2. CONCLUSION: From above result, there was no evidence of loss of epidural negative pressure affecting on the spinal sensory blockade level.