Cryptococcal meningitis is a several disease common in late stage of HIV infection. Detection of cryptococcal antigen (CrAg) is an important for early diagnosis of this invasive mycosis. The pre-emptive treatment for isolated antigenemia prevents the onset of meningoencephalitis. Screening CrAg in patients with low CD4 count is cost-effective in countries with prevalence of antigenemia above 3%. However, in Brazil, the number of prevalence studies on cryptococcosis and HIV is insufficient. The objective of this study is to estimate the prevalence of CrAg and describe clini-cal characteristics from a cohort of patients followed at a reference center in Brazil. CrAg screening was performed in 89 inpatients with CD4 count ≤200 cells/mm3 or WHO stage III/IV from the National Institute of Infecttious Disease, Rio de Janeiro. Patients with isolated antigenemia received pre-emptive therapy with fluconazole and patients with meningoencephalitis were treated with Amphotericin B. Individuals were followed up for 12 months. Prevalence of serum CrAg was 11.23%, cryptococ-cal meningoencephalitis 6.74% and isolated antigenemia 4.81%. None of the patients with isolated antigenemia developed meningoencephalitis during the follow up. Signs and symptoms of meningoencephalitis were unspecific or absent. Our study suggests the need of CrAg screening in Brazil and highlights that lumbar puncture is manda-tory in all individuals CrAg positive to exclude asymptomatic meningoencephalitis.