Purpose: To determine the location of mucosal injuries that appear following placement of complete dentures, as well as the number of adjustments necessary to achieve patient comfort. The frequency of mucosal injuries in female and male patients and their connection with clinical anatomic features were also investigated. Materials and Methods: Sixty-one completely edentulous healthy patients who wore dentures (47 women and 14 men) took part in the study; 122 newly fabricated complete maxillary and mandibular dentures were investigated. All patients were seen for a 1-week adjustment appointment. Areas where signs of denture-induced mucosal injuries appeared were marked on an anatomic illustration. The follow-up period was in 1-week increments as deemed necessary by the patient. Associations between variables were analyzed with analysis of variance. Results were recorded as mean ± SD. Statistical significance was set at P £ .05. Results: Eighty-seven percent of the dentures required adjustment at week 1, 50% at week 2, and only 7% at week 3. No patients required a further visit. Most frequently injured maxillary areas were the vestibular sulcus (41%), maxillary tuberosity (21%), and hamular notch (12%). In the mandible, the most frequently injured areas were the retromylohyoid area (17%), lingual sulcus (14%), and vestibular sulcus (13%). Denture-induced irritations were detected in a higher ratio in the mandible (P .001), especially in male denture wearers at the first adjustment (P .05). Men had a higher ratio of lesions at the region of the maxillary vestibular sulcus between the labial and buccal frenum and at the mandibular vestibular sulcus of the buccal shelf region (P .001). Conclusions: Denture-induced irritations appeared most often in the vestibular sulcus of the maxilla and mandible, indicating that it is necessary to evaluate the area of the facial seal of the prosthesis by applying a medium- or a heavy-pressure indicator paste to the borders, and to make adjustments at the delivery stage and subsequent adjustment appointments. Denture placement must not be the final patient-clinician encounter when treating with complete dentures. Denture adjustments are very important clinical phases of denture fabrication and essential in patient care