The purpose of this study was to determine the perception of discomfort over time by a group of 70 patients undergoing orthodontic treatment. Patients who were selected for comprehensive orthodontic treatment completed questionnaires before insertion of separators and initial arch wires and after placement at 4 hours, 24 hours, and 7 days. The level of discomfort during these time periods was assessed by a visual analogue scale. The results showed a significant increase in the level of discomfort after insertion of either separators or arch wires at 4 hours and 24 hours, but not at 7 days. No significant difference was found in the level of discomfort of patients more than 16 years of age compared with those 16 years and under. No significant difference in discomfort was found between the sexes. These results are useful in relating expectations of discomfort to patients who undergo orthodontic treatment.