To evaluate the influence of mid treatment hemoglobin level with the other prognostic factors on the outcome in patients with Tis-T1N0 glottic carcinoma treated with radiotherapy (RT). Between October 1995 and December 2008, a total of 84 patients diagnosed with Tis-T1N0 glottic carcinoma were treated with definitive RT. The influence of tumor, treatment, and patient-related factors on local control (LC) and overall survival (OS) were analyzed. The median follow up time was 30 months (ranges, 4-180 months). Local and/or locoregional relapse was observed in 11 patients (13%) (3 locoregional and 8 local). The estimated 5- and 10-year LC and OS rates were 87%, 85%, and 87%, 70% for the entire study group, respectively. Multivariate analyses revealed that older age (>= 50 years) and the use of wedge-filter were found to be favorably influencing the LC (p= 0.025 and p= 0.030, respectively). Mid treatment hemoglobin level more than 13 g/dl was determined statistically significant for improving both LC and OS (p= 0.011 and p= 0.021). Older age and use of wedge filter were found to be independent prognostic factors for LC. Mid treatment hemoglobin level of more than 13 g/dl was correlated to superior LC and OS rates. Monitoring the changes of hemoglobin levels during therapy has to be considered to improve the outcome.