The effects of age were investigated on characteristics of spinal analgesia with hyperbaric bupivacaine in 38 younger patients (less than 50 yr: group I), and 48 older patients (greater than 80 yr: group II). Four millilitre of 0.375% bupivacaine in 2.5% dextrose was injected via the L3-4 space in a lateral position, and the patients were immediately turned supine. In group II, the time to maximum spread was significantly shorter, and the sensory spinal blockade higher (one dermatome) than in group I. The mean sensory recovery of the two uppermost segments did not differ between the two groups. The mean duration of analgesia at the L2 level was increased by only 15 min in the older group. Complete motor blockade of the lower limbs developed most rapidly in group II, while duration of all degrees of motor blockade did not differ significantly with age. Because of great individual variation, the clinical significance of such differences is limited. In the older group, there was a greater decrease in systolic arterial pressure from resting values, despite rapid infusion of lactated Ringer's solution.