Oral manifestations occur at all stages of human immunodeficiency virus (HIV) infection. Their clinical expressions and severity depend on the evolution of the infection and become critical at the stage of acquired immunodeficiency (AIDS). They are essentially infectious, tumoral, and, starting a few years ago, iatrogenic. Infections are mostly fungal (candidiasis), viral (herpes, zoster, human papillomavirus infections, etc.), and less frequently bacterial (streptococcemia). Cases of sexually transmitted diseases, particularly syphilis, are multiplying preoccupyingly. The most frequently observed tumors are Kaposi's sarcoma. Drug intolerance is common; the symptoms are mostly dermatological, but also oral (Stevens-Johnson syndrome and toxic epidermal necrolysis) when sulfonamides and certain antiretrovirals are used. The advent of prolonged Highly Active Anti-Retroviral Therapies (HAARTs) has led to a decline in the incidence of most opportunistic conditions, infections and tumors (except for multiple oral warts and zoster). HAARTs also provoke adverse reactions such as lipodystrophy syndromes (signs of peripheral atrophy and central hypertrophy, associated in varying degrees with metabolic syndromes). Extended survival and the new methods for prophylaxis of opportunistic infections have gradually modified diagnostic and therapeutic strategies for oral manifestations of HIV infections.