© 2015 Springer Science+Business Media New York (outside the USA) Lower nadir CD4 cell counts and higher HIV viral loads are associated with increased risks of adverse events in the progression of HIV disease. In cases where medical records are inaccessible or incomplete, little evidence is available regarding whether nadir CDR cell count or HIV viral load is reliably reported in any patient population. We compare survey data collected from 207 HIV-infected individuals detained in San Francisco jails to data collected from electronic medical records (EMR) kept by the jails and community health providers. The sensitivity of self-reported nadir CD4 cell count less than 200 was 82 % [95 % confidence interval (CI) 68, 88], and the sensitivity of reporting an undetectable most recent HIV viral load was 93 % (95 % CI 84, 97). This suggests that in a highly socially marginalized population, nadir CD4 cell count and most recent HIV viral load are recalled accurately when compared to EMR.