PURPOSE: to check the effect of speech and language therapy on a group of mouth breathers, as well proposing a minimum therapy for mouth breathing treatment. METHOD: longitudinal prospective study, casuistic on 40 mouth breather subjects who were patients from the Otorhinolaryngology Ambulatory of UNICAMP Hospital. On weeks 0, 12 and 24, we proceeded photographical documentation, clinical assessment, and protocol application in order to categorize the breathing mode, posture (lips and cheeks), strength and movement (lips, cheeks and tongue). The applied therapeutic proposal consisted of practicing and awareness on nasal breathing; maneuvers to warm and vascularize the orofacial muscles; application of points and motor zones on the face; passive maneuvers; use of distal impulse; myofunctional exercises and register of patients perception on their olfactive conditions and nasal obstructions. A non-parametric two proportion equality test was used, p < 0.05. RESULTS: nasal breathing function was adjusted. Increase on lip, tongue and cheek strength. Improvement on the movement: lips pouted to the right and left, snap and lip vibration. Vibration and snap of tongue. Simultaneous inflation of the cheeks, inflation of left and right cheeks alternately. The highest therapeutic gain occurred on 12 weeks. From such data it was possible to come up a protocol made up of 12 structured sessions using the strategies from this study. CONCLUSION: the study has demonstrated the effectiveness of using myofunctional rehabilitation for mouth breathers, and the highest therapeutic evolution took place during the 12th week.