BACKGROUND: Epidural analgesia and remifentanil patient-controlled analgesia are two popular techniques for the treatment of labour pain, each with its own efficacy and toxicity. METHODS: Parturients requesting analgesia were randomly assigned to either patient-controlled intravenous remifentanil or epidural analgesia. Control patients consisted of parturients not requesting pain medication. The primary objective was to compare the incidence of maternal fever (temperature ⩾ 38°C); secondary outcomes included the incidence of low oxygen saturation, pain scores, nausea and vomiting, sedation scores, pruritus and neonatal outcome. RESULTS: Data from 140 parturients were analysed: 49 received remifentanil analgesia, 49 epidural analgesia and 42 no analgesia (controls). Fever (temperature ⩾ 38°C) developed in 10% of remifentanil patients compared to 37% of epidural patients and 7% of control patients (P<0.001). One or more hypoxaemic events (oxygen saturation <90% for at least 1 min) occurred in 48% of patients on remifentanil versus 15% of patients on epidural analgesia and 20% of control patients (P=0.003). Although pain intensity scores differed significantly between the two groups in favour of the epidural, mean satisfaction scores were similar in both analgesia groups (remifentanil 8.1 ± 1.2 vs. epidural 8.4 ± 1.2). Remifentanil analgesia was associated with a higher incidence of nausea and deeper levels of sedation. The differences in haemodynamic parameters between groups were small and clinically insignificant. CONCLUSIONS: During treatment of labour pain, epidural analgesia is associated with a higher incidence of maternal fever, while remifentanil analgesia results in more frequent and deeper hypoxaemic events.