Purpose: To evaluate the prevalence and the impact of malocclusions on the quality of life of 18-year-old young male adults. Materials and Methods: Cross-sectional study involving young adults who applied for military service in the city of Florianópolis in the year 2003 (N = 3735). The sample size was 414 individuals randomly selected during the health examination days. The malocclusion data were obtained through the Dental Aesthetic Index variables. The impact of the oral health conditions on the quality of life was obtained through the Oral Impact on Daily Performance. Results: The highest prevalence was the molar relationship in mesio- or disto-occlusion with 57.3% (95%CI 52.5 - 62.1); 36.4% (95%CI 28.6% - 4.2%) of the applicants reported an impact on their quality of life as a result of the oral health condition. Results from the multiple logistic regression analysis showed that only the incisal crowding [OR 1.9 (95%CI 1.2 - 3.1)] (p = 0.008) showed an impact on the applicants' quality of life. Conclusion: The malocclusion of highest prevalence was molar relationship disorders (57.3%), and only the dental crowding generated an impact on the quality of life. Keywords: malocclusions, epidemiology, self-perception, impact, young adults