The aim of this study was to assess changes in oral health-related quality of life (OHRQoL) among patients wearing fixed orthodontic appliances after 24 hours fixation. A prospective cohort study was carried out on 20 patients aged 14-24 years old which required fixed orthodontic appliances at Post-graduate clinic in University Malaya. Self-administered modified short version of the Oral Health Impacts Profile (OHIP-16) questionnaire was used to assess the OHRQoL among patients before treatment and after 24 hours fixation of orthodontic appliances. Score of OHRQoL was calculated by adding up responses codes. The score range from 16 to 80 with high score indicated poor OHRQoL. Based on distribution, paired-t test or Wilcoxon signed ranks test were used for significant test. Preliminary finding showed that total score of OHRQoL increased significantly after 24 hour fixation (mean 45.4 ± 9.1) as compared to before fixation (mean 35.8 ± 9.6) (p<0.001). Significant changes were found for the following items: difficulties of chewing (p<0.001), discomfort in eating (p<0.001), avoidances of eating certain foods (p<0.001), pain (p<0.001), difficulties in pronunciations (p<0.001), disturbed sleep (p<0.001), lack of self-confident (p<0.005), ulcer (p<0.05) and embarrassment (p<0.05). In conclusion, OHRQoL was found to deteriorate after 24 hours fixation of orthodontic appliances in almost all domains except social disability and handicap.