BACKGROUND: Opportunistic infection (OI) is the most significant complication of the human immunodeficiency virus (HIV). Differences in the characteristics of HIV patients make the prevalence of Opportunistic infection different between regions. The study aimed to identify variables associated with OI incidence among HIV-infected patients in Semarang City, Indonesia.METHODS: This study uses secondary data sourced from special HIV surveillance for 2019-2021 with a cross-sectional method. 1362 HIV patients with variables health care facilities; year of diagnosis; area of ​​residence; age; sex; pregnancy status; occupation; risk factors; risk group determined based on purposive sampling were included in the chi-square analysis and logistic regression.RESULTS: This study showed 12.3% (n=167) of HIV patients experienced OI, where OI was more common in HIV patients with risk groups of sex workers (28.70%), high-risk partners (18.60%), and Male Sex with Men (MSM) (15.40). The most common types of OI were tuberculosis infection (43%), candidiasis (21%), and diarrhea (9%). Age was the variable most associated with the incidence of OI (p-value 0.001).CONCLUSIONS: Age groups 45-54 years and 55-64 years have the most influential association with Opportunistic infection incidence in HIV patients, so planning an appropriate intervention program for this subpopulation is necessary.KEYWORDS: HIV patients, Opportunistic Infections, risk factors, cross-sectional