Background: C-reactive protein, an acute-phase plasma protein and a non-specific marker of systemic inflammation, has been found to be of independent prognostic value in a variety of disease processes, including HIV/AIDS. The few studies reported so far, have shown promise in using CRP as a marker of HIV disease progression. Objective: The objective of this study was to determine the correlation between CRP and CD4+ cell count in HIV-infected patients at the University of Maiduguri Teaching Hospital; and to compare with HIV/PTB co-infected patients as well as HIV-seronegative healthy age- and sex-matched controls. Methods: A hospital-based cross-sectional comparative study was undertaken. One hundred and twenty consecutive HIV-infected patients comprising 60 HIV+ only and 60 HIV/PTB co-infected patients and 60 apparently healthy HIV- seronegative age- and sexmatched controls were recruited. The serum CRP measurement was determined by using high-sensitivity CRP ELISA kit. The CD4+ cell counts of both cases and controls were determined, while, HIV-1 viral load was also determined in the cases. Chi square (χ2 ) or Fisher’s exact was used to find the relation between demographic variables. Student t-test was used to determine the difference between mean CRP, CD4+ cell count and HIV-1 viral load. Pearson’s product moment correlation coefficient (r) was used to determine the relation between CRP and CD4+ cell count and HIV-1 viral load. The method of Galen and Gambino was used to find the sensitivity, specificity, positive and negative predictive values of the tests. Results: The Pearson’s product moment correlation coefficients (r) for the correlation between CRP and CD4+ cell count were -0.596 (p=0.000) for HIV+, -0.365 (p=0.004) for HIV/PTB patients and +0.147 (p=0.263) for healthy controls. Whereas, the Pearson’s product moment correlation coefficients (r) for the correlation between CRP and HIV-1 viral load were +0.023 (p=0.859) for HIV+ patients and +0.097 (p=0.463) for HIV/PTB patients. The diagnostic usefulness of the CRP measurement as a surrogate for CD4+ cell count showed sensitivity, specificity and positive predictive values of 80.6%, 72.4% and 75.8% for HIV+ patients and 88.9%, 63.6% and 66.7% for the HIV/PTB patients. The means ±SD of CRP and CD4+ cell count of the study subjects were 11.96±4.34 mg/L, 13.74±4.98 mg/L, 3.16±3.55 mg/L and 313±233 cells/µL, 306±162 cells/µL, 921±173 cells/µL for HIV+, HIV/PTB and controls, respectively. While, the means ±SD of HIV-1 viral load were, 63,800±96,199 copies/ml and 89,400±125,097 copies/ml for HIV+ and HIV/PTB patients, respectively (p=0.211). Conclusion: This study found a strong linear negative correlation between CRP and CD4+ cell count in HIV-infected patients as well as those with HIV/PTB co-infection. Therefore, serum CRP level of >10mg/L in HIV-infected patients, can be used to predict low CD4+ cell counts for possible commencement of ARV or during treatment follow-up in resource poor locations lacking the facility for measuring CD4+ cells.