A pre- and intraoperative evaluation by videolaryngostroboscopy (VLS) and saline infusion (SI) into Reinke's space was prospectively applied to a cohort of 52 patients with mid-vocal cord erythroleukoplakias observed at our institution between January 1997 and June 1999. These tests were done to predict the invasion of the layered structure of the lamina propria and consequently determine the deep extent of the excisional biopsy to be carried out. According to the results of these examinations, carbon dioxide laser resections were performed as follows: 25 Type I, 17 Type II and 10 Type III cordectomies according to the European Laryngological Society Classification. Histopathologic diagnoses were keratosis without atypia in 13 patients, keratosis with mild, moderate or severe dysplasia in 8, 3 and 5, respectively, microinvasive carcinoma in 12 and invasive carcinoma in 11. By comparing the type of resection with the pathologic diagnosis obtained on the specimen and its surgical margins, we estimated the number of under- and overtreatments. In addition, an assessment was made on specificity, sensitivity, positive and negative predictive values and accuracy of VLS and SI, both independently and in combination. Thirty-eight patients (73%) received the correct type of resection, 1 patient (2%) an undertreatment and 13 (25%) an overtreatment. VLS and SI showed a specificity, sensitivity, positive and negative predictive values and accuracy of 82, 100, 94, 100, 97% and 90, 83, 86, 87 and 87%, respectively. The VLS/SI combination raised the values to 89, 100, 88, 100 and 94%. The 4-year overall and disease-free survival and ultimate local control with laser alone were 90, 94 and 100%.