Background: The authors recently showed that “mobile” epidural analgesia, using low-dose local anesthetic–opioid mixtures, reduces the impact of epidural analgesia on instrumental vaginal delivery, relative to a traditional technique. The main prespecified assessment of pain relief efficacy, women’s postpartum estimates of labor pain after epidural insertion, did not differ. The detailed analgesic efficacy and the anesthetic characteristics of the techniques are reported here. Methods: A total of 1,054 nulliparous women were randomized, in labor, to receive boluses of 10 ml 0.25% bupivacaine (traditional), combined spinal–epidural (CSE) analgesia, or lowdose infusion (LDI), the latter groups utilizing 0.1% bupivacaine with 2 g/ml fentanyl. Visual analog scale pain assessments were collected throughout labor and delivery and 24 h later. Details of the conduct of epidural analgesia, drug utilization, and requirement for anesthesiologist reattendance were recorded. Results: A total of 353 women were randomized to receive traditional epidural analgesia, 351 received CSE, and 350 received LDI. CSE was associated with a more rapid onset of analgesia, lower median visual analog scale pain scores than traditional in the first hour after epidural insertion, and a significant reduction in bupivacaine dose given during labor. Pain scores reported by women receiving LDI were similar to those in the traditional group throughout labor and delivery. Anesthesiologist reattendance was low but greater with each mobile technique. Conclusions: Relative to traditional epidural analgesia, LDI is at least as effective and CSE provided better pain relief in the early stages after insertion. The proven efficacy of mobile epidurals and their beneficial impact on delivery mode make them the preferred techniques for epidural pain relief in labor.