We conducted a prospective observational study to determine the clinical features, the degree of immunosuppression, and the prevalence of human immunodeficiency virus type 1 (HIV-1) infection associated with herpes zoster in Kenya. The study included 196 HIV-1 positive individuals and 34 HIV-1 negative individuals between the ages of 16 and 50 years who presented to a referral clinic in Nairobi. Comparison of the clinical characteristics in the two groups found that the duration of illness in the HIV-1-positive group was longer (32 vs. 22 days; P < .001) and that the HIV-1-positive group was more likely to have generalized lymphadenopathy (74% vs. 3%; OR: 12.2; 95% CI: 1.6, 91.7), severe pain (69% vs. 39%; OR: 3.6; 95% CI; 1.7, 7.6), bacterial superinfection (15% vs. 6%; OR: 5.7; 95% CI: 1.3, 25.0), and more than one affected dermatome (38% vs. 18%; OR: 2.8; 95% CI: 1.1, 8.0). Dermatomal distribution of the lesions was similar in the two groups, except for cranial lesions, which occurred exclusively in the HIV-1-positive group. The mean CD4 T lymphocyte count at presentation was 333/mm(3) in the HIV-1-positive group and 777/mm(3) in the HIV-1-negative group (P < .001). Herpes zoster is often recognized as the initial HIV-1-related illness in Kenya despite the fact that patients have moderate to severe depression of CD4 cell counts at presentation. Although the clinical features of herpes zoster may be more severe in HIV-1-positive individuals, recovery is generally complete and uncomplicated.