Background: Homeless population has been severely affected by the COVID-19 pandemic. Their living conditions, comorbidity with different pathologies and a greater frequency of mental disorders, make this population vulnerable. Method: We implemented a program of serial visits in a hostel for confined homeless of the city council social services, for the monitoring and treatment of mental disorders and substance abuse problems. Accompanied by serial phone and email contacts. Results: A highly significant percentage (63%) had mental disorders or substance abuse, requiring pharmacological intervention, and 37% began follow-up in resources of the Mental Health and Addiction network of the Psychiatric Service at the end of the program. Hospital emergency service visits were drastically reduced. None of them were infected with COVID-19. An individualized Social plan was drawn up in order to reintegrate them with support in the community. Conclusions: The Results have been really positive, meeting all the objectives and opening up developing new programs in the future, in the pandemic outbreak and out of it.