Objectives: Orthodontic thermoelastic archwires produce lighter and more biologic forces than superelastic archwires and could therefore offer the possibility of reducing initial orthodontic pain. Nevertheless, evidence concerning this issue is scarce. The aim of this study was to compare pain perception following first archwire placement in patients with thermal heat-activated (HANT) and superelastic (SE) nickel-titanium archwires. Method and Materials: Thirty subjects (11 males, 19 females; range, 11 to 26 years of age) were recruited. Metal brackets were bonded in the maxillary or mandibular arch. Round 0.016- inch HANT or 0.016-inch SE archwires were randomly placed and tied with elastic ligatures. Each patient was invited to score tooth pain for 7 days at different time points (8:00, 12:00, 16:00, 20:00, and 24:00) using the visual analog scale (VAS). Results: In both groups, pain was highest at day 2 and lowest at day 7. Patients with HANT archwires had significantly lower VAS scores (P .005) at days 2, 3, and 4 than subjects with SE archwires. This was also the case after adjusting for analgesic consumption, sports practicing, overlapping pain of different origin, and the concomitance of stressful events. The frequency of analgesic consumption was higher in the SE than in HANT group at day 3 (P .05). No differences in pain perception were found between time points, nor was any correlation found between dental crowding and pain. No difference in pain perception was found between the maxillary and mandibular dental arches. Conclusion: Initial orthodontic pain is reduced when using HANT orthodontic archwires. Keywords: orthodontic pain, superelastic archwire, thermoelastic archwire