Background and objectives: Transoral laser microsurgery (TLM) is widely accepted for its advantages, which consist of a brief hospital stay, rapid functional recovery, low management costs and the fact that it can be easily repeated in cases of recurrence. However, a high incidence of positive or narrow surgical margins has been reported in the literature, even if controversy still exists on the prognostic significance of positive resection margins. The aim of the study was to evaluate the utility of toluidine blue staining in defining the resection margins of early glottic cancer (T1a–T2) treated with TLM. Materials and Methods: This retrospective study was conducted on patients with early glottic cancer (T1a–T2) managed by TLM. A group of patients treated between 2010 and 2014 underwent toluidine blue staining (TB group) of the lesions before starting the cordectomy by TLM, and a group of patients treated by TLM between 2006 and 2009 was considered the control group. Results: A total of 44 subjects were included in this study: 41 were men, and 3 were women. The mean age was 58 ± 9.0 years (median 59.0, range 41–77). Twenty-three of the 44 patients were included in the TB group and 21 in the case control group. In the TB group, only the positivity of the deep margin was a predictor of local recurrence (p = 0.037), while in the control group, positive or close margins and the type of cordectomy were predictive factors of local recurrence (p = 0.049). Considering the TB group and control cases, the 5-year local recurrence-free survival was 95.6% and 80.9%, respectively (p = 0.14). Conclusions: From this first study, toluidine blue staining seems to be a useful modality to improve the rate of the negative resection margins of early glottic cancer (T1a–T2) treated by TLM.