<p>The use of information and communication technologies, particularly web-based interventions, is an innovative, efficient way to deliver psychological care and reduce traditional treatment barriers. Although there is evidence of their efficacy in reducing substance use, few studies have been undertaken in Mexico. Implementing technology-based interventions in clinical settings requires considering various issues related to the people involved and their contexts, such as available infrastructure, institutional policy, and the clinical abilities of the mental health professionals involved. This qualitative study explores the barriers and facilitators of the implementation of a guided, web-based intervention to reduce substance use and depressive symptomatology from the point of view of 52 mental health professionals who reported using some form of ICTs with their patients prior to the study. The thematic analysis yielded five analytic categories and 11 sub-categories. The results suggest the influence of numerous factors related to the implementation of web-based interventions and the use of technology in general. The main barriers identified are the need for material and technological infrastructure, training in clinical approaches and technological tools, and institutional policies to promote the incorporation of technology into everyday clinical practice. Participants expressed their openness and willingness to use technology in their everyday clinical practice. However, the study showed that various challenges are related to the organizational context and institutional health care policy rather than the attitudes and abilities of mental health professionals.</p>