In this document, psychotherapeutic practice is described from a perspective of science and evidence, using as an instrument the definitions, descriptions, and conceptualizations subsequently supported by a naturalistic and non-mediational position. Starting from the conception with psychotherapy free of union biases or any particular approach. First, a description of what it is and its phases is addressed. Then, conceptualizations in psychotherapy of personal and social problems and procedures were established. Finally, this document concludes based on the criteria proposed by the (American Psychological Association (APA), 2006) and the Plan for Comprehensive Action on Mental Health (World Health Organization, 2013) for a practice based on evidence.