The behavior of organizations is associated with a set of rules and norms present in the exchange processes between them and the environment. The institutionalization of corporate social responsibility (CSR) practices is currently advancing. With this, this study aims to verify which isomorphic mechanisms are present in the institutionalization of CSR practices. For this purpose, descriptive research, field study and quantitative approach were used. As a data collection instrument, a five-point Likert scale questionnaire sent by e-mail was used. The population studied is the automotive dealers of Rio Grande do Sul, and the sample consists of 24 companies, which answered the instrument. The findings indicate that for the economic and legal dimensions, the institutionalization of CSR practices according to the managers' perception is from strong to very strong and for the ethical dimension, the intensity of CSR practices is medium to strong. The perceived by employees, indicates strong to very strong intensity in CSR practices for the economic dimension and medium to strong intensity for the legal and ethical dimensions. For managers, the isomorphism that most interferes with CSR practices is coercive with medium to strong intensity and the least that interferes is mimetic with strong presence intensity. The perception of employees indicates that the coercive, mimetic and normative isomorphic mechanisms have a similar participation in the institutionalization of CSR practices, with medium to strong intensity.