In 13 full-term primipara in active labor an initial single dose of preservative-free meperidine (100 mg) diluted in 10 ml of saline was injected epidurally (L2-3). In another 13 full-term parturients in active labor, 10 ml of bupivacaine 0.25% was used. Pain was scored by the linear analog scale. Onset of analgesia was 5.3 +/- 2.8 minutes following administration of meperidine, and 12.9 +/- 6.9 minutes following bupivacaine (p less than 0.01). Pain score decreased to 0 in 12 of 13 patients following meperidine administration and in six of 13 patients following bupivacaine (p less than 0.01). Satisfactory analgesia lasted 160.8 +/- 90.3 minutes following meperidine, and 103.5 +/- 42 minutes following bupivacaine administration (p less than 0.01). Subsequent supplementation by intermittent doses of 10 ml of bupivacaine 0.25% was more effective and less frequent following meperidine than following bupivacaine administration. Maternal sedation, nausea, and itching occurred frequently following administration of epidural meperidine, whereas hypotension, numbness, and motor dysfunction followed bupivacaine. In neither group was significant respiratory depression observed. All parturients delivered vaginally, 288 +/- 212.6 minutes following meperidine and 348 +/- 195.8 minutes following bupivacaine administration (p greater than 0.05); the neonates showed normal Apgar scores and neurobehavioral responses. Epidural meperidine, supplemented by subsequent bupivacaine as indicated, provides maternal sedation and satisfactory analgesia, and it diminishes the requirements of bupivacaine supplementation. The technique is advantageous in the parturient primipara.