The aim of this study is to evaluate the effectiveness of the laryngostroboscopy for monitoring the evolution of patients with functional dysphonia before and after the logopedic vocal treatment. We performed a prospective observational study of 65 dysphonic patients diagnosed of functional dysphonia, where we analyzed four stroboscopic parameters (glottal closure, vocal fold vibration, mucosal wave and phase symmetry) by a protocol based on systematic subjective evaluation of the stroboscopic images before and after the rehabilitator treatment; and the results were stratified according to the clinical course. All patients, before the treatment, had some abnormality in at least one of the four analyzed aspects. After the vocal treatment, we found improvement of the four parameters in different degrees, and we just found a statistically significant relationship between the evolution of the glottal closure and the clinical course. We believe that the laryngostroboscopy, systematized through a protocol, is a useful technique for the diagnosis of functional abnormalities in patients with functional dysphonia but it is not a very useful technique for evaluating the results after the rehabilitator treatment, as there is not a statistically significant relationship between clinical course and the change in the most stroboscopic parameters, so it shouldn’t be the only technique used for these proposes.