The introduction of highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV) infection from a rapidly progressive catastrophic illness to a chronic condition. Individuals with HIV are living longer and developing conditions usually associated with aging, as well as complications from pre-existing or subsequently acquired conditions. In addition, toxicities associated with HAART may precipitate or exacerbate comorbid conditions. As opportunistic infections account for fewer admission and lower mortality rates, new patterns of illness are emerging. Complex interactions among multiple, sometimes overlapping conditions require focused yet comprehensive attention in care and management. Nurses will encounter HIV-infected patients in an increasing range of care settings, and an understanding of the range and interaction of potential comorbidities and their treatments with HIV and its treatment will be required to provide safe and effective care.