Background: Dual diagnosis (DD), as the co-occurrence of a substance use disorder and a psychiatric disorder, is underestimated, under-diagnosed and often poorly treated throughout the world, although it is highly prevalent in people suffering from a mental disorder. Aims and methods: This review analyzed 48 studies from a PubMed and PsycINFO databases search, in order to verify the state of the art regarding the organization of community health services for DD treatment. Results: Four macro-themes have been identified: service organization, critical issues, assessment tools and evidence-based interventions. An effective service recognizes the complexity of DD, promotes a common staff culture, and tailors the organization to local needs. The main critical issues in its implementation include the lack of specific staff training, the poor management of resources and the need for greater personalization of care plans, with attention to psychosocial interventions. Integrated service assessment tools can be used as a benchmark measure at the program level for implementation planning and at the national level to affect policy change. The integrated treatment model for DD should also aim to improve access to care and offer treatments based on scientific evidence. It is also evident that the integration of services can improve outcomes but it is not a guarantee for it. Conclusion: There is an urgent need to improve networking between mental health and addiction services in order to deal with DD and create new integrated intervention models, paying attention to an approach to the whole person, seen in his/her absolute uniqueness.