Serious neurologic complications rarely occur after spinal anesthesia. Historically, the reported frequency of persistent sensory or motor deficits has ranged from 0.005% to 0.7%. However, the introduction of small-gauge needles and new local anesthetics and intrathecal adjuvants makes it necessary to reevaluate the frequency of neurologic complications after spinal anesthesia. This study is a retrospective review of 4767 consecutive spinal anesthetics performed between June 1987 and June 1990. Mean patients age was 65 +/- 15 yrs. There were 3560 (74.7%) men and 1207 (25.3%) women. A preexisting neurologic condition was present in 481 (10.1%) cases. The surgical procedures were genitourinary and lower extremity orthopedic in 4348 (91.2%) cases. A paresthesia was elicited during needle placement in 298 (6.3%) cases. Six patients reported pain upon resolution of the spinal anesthetic (persistent paresthesia). Four persistent paresthesias resolved within 1 wk; the remaining two resolved in 18-24 mo. The presence of a paresthesia during needle placement significantly increased the risk of persistent paresthesia (P < 0.001). There, were also two infectious complications. One patient with recent (treated) urosepsis underwent a urologic procedure under spinal anesthesia and subsequently developed a disc space infection. The second patient developed a paraspinal abscess. Both were treated with surgical drainage and antibiotics and remained neurologically intact. There were 62 (1.3%) patients with a postdural puncture headache, including 23 (0.5%) who underwent an epidural blood patch. These results are similar to those of previously published reviews and demonstrate the continued safety of spinal anesthesia.