In region of Vale do Rio Pardo, situated in Rio Grande do Sul, Brazil, the production of tobacco is an important source of income, especially for family farmers. The discussion around tobacco production in the academic researches and society’s debate involves: the problems that smoking causes in human health and the same time, the role of farmers have been developed in the productive chain. In view of this, the aim of this article was to understand the trust relation between farms and the field technicians in the Vale do Rio Pardo region and the south side area of the Rio Grande do Sul, Brazil. 142 interviews have been accomplished with families that are producing tobacco, using a semi-structured form (qualitative and quantitative questions). The Likert scale, field diaries and observations were used as search tools. When farmers have been questioned about trust in agricultural technicians (using Likert scale), the answers were similar in the three cities: the southern Rio Grande do Sul, in Dom Feliciano, confidence is 69.7%; in the Vale do Rio Pardo, Rio Pardo and Santa Cruz do Sul, respectively, confidence is 63.3% and 64.6%, according to levels between “agree” and “disagree totally”. Besides, in this context, there is direct relation between trust in the field technicians and integration of tobacco. The informal relation between farms and the field technicians has been changed by formal contracts. Nevertheless, informality was relevant, specifically because it may help to understand how the trust emerges in friendships and family relations.