Work is an activity that has always been part of humanity, being an important factor in one's quality of life, however, it can also produce suffering and generate illnesses, especially when the relationships that occur in working environment do not offer the necessary support to fight stress and distress from work routine. This research aimed to investigate the influence of labor relations and social support on the mental health of seamstresses. This is a cross-sectional descriptive study with combination of quantitative and qualitative approaches and was conducted with 56 seamstresses of four sewing factories from Formiga-MG. The data relating to social support and mental health conditions were obtained by applying three psychometric scales, namely: the perceived social support scala (EPSST), SRQ-20 (Self-Report questionarie) and Alcohol, Smoking and Substance Involvement Screening Test (ASSIST). The scores obtained from each scale were submitted to nonparametric statistical tests Chi-square and Fisher's exact test with the sociodemographic data, in order to verify the association between those variables. A focus group has been conducted in order to ascertain wether labor relations contribute to mental illness of these women from their perception. During the study, all ethical guidelines and standards proposed by Resolution 466/2012 of the National Health Council for research involving human subjects have been considered, with the approval by the Ethics and Research Committee of the Ribeirão Preto School of Nursing University of São Paulo. Regarding the results, there was a predominance of female workers with low education, which self-declared white and had no husband or non-marital partner. Relying on the SRQ-20 score it has been identified that more than half of the interviewed seamstresses (53.6%) had indicative symptoms of common mental disorders, and most of them, said they did not receive or have doubts about the social support at work. Significant association between the scores of these two latter variables was not identified. There was a low prevalence of substance use among the interviewed women. It was also possible to identify that the sewing activity has many precarious features and that these workers perceive their labor relationships as supportive and also identify stressful situations in these relationships that contribute to the distress and suffering.