Introduction and Aims of the Study Teachers constitute professional category with high occurrence of voice disorders due to this occupation's intense vocal demand and to unfavourable work environments. To identify job's factors associated to voice disorders in teachers of the public school of the city of São Paulo.

Methods This is matched case-control study. The case group was teachers with vocal quality deviations and vocal fold lesion or altered larynx. The control group was selected at the same schools in which the case group individuals worked. Both groups answered the questionnaires: Conditions of Vocal Production-Teacher(CVP-T), Vocal Handicap Index (VHI), Job Stress Scale (JSS) and Work Ability Index (WAI). The analysis was done using qui-squared association test and multiple regression models.

Results 78.8% of the control group are concentrated in lower levels of demand of job stress, while 69.3% of the case group are located at higher levels (p=0.019). Regarding work control, 63.1% of the control group had higher levels of control, while 73.1% of the case group are in the lower categories (p=0.034). There is a significant association between low work ability and voice disorder (p<0.001). This association is maintained in the multivariate analysis, where low (OR=9.5, p=0.001) and moderate (OR=6.7, p<0.001) capacity for work were also associated with voice disorder.

Conclusions Low and moderate ability to work show high correlation with the presence of voice disorder. The presence of voice disorder may jeopardise their careers because these professionals depend essentially on their voices to teach.