Abstract INTRODUCTION: The objective was to identify comorbidities related to HIV-positive patients in Blumenau, State of Santa Catarina. METHODS: A retrospective, descriptive observational design study which analyzed data from 424 patients assisted by the sexually transmitted disease/acquired immunodeficiency syndrome (STD/AIDS) Specialized Care Service (SCS). RESULTS: Of 424 medical records analyzed, 388 patients presented CD4+/CD8+ ratios lower than 1. The most prevalent comorbidities were smoking, depression, alcoholism, and herpes zoster infection, in males and females. CONCLUSIONS: The most relevant comorbidity in both genders was herpes zoster, an important marker of immunity in patients. The lowest mean was observed among patients with neurotoxoplasmosis.