Introduction
According to the World Health Organization, Nigeria remains one of the worst affected countries with HIV and Mycobacterium tuberculosis infections in the world. Of a critical concern is the emerging threat of co-infection at an unprecedented proportion in the country. In south-west Nigeria, few studies have assessed the prevalence of HIV infection among TB patients. Findings aimed at estimating the prevalence of HIV co-infection among TB patients enrolled in a teaching hospital in Ogun State, south-west Nigeria between 2008 and 2011 are presented in this study.

Materials and methods
This is a retrospective study of 386 TB patients admitted between January 2008 and 2011 to Olabisi Onabanjo University Teaching Hospital, Ogun State, Nigeria of which 206 (53%) were males and 180 (47%) were females. Descriptive statistics, chi-square test and logistic regression were utilized in the analysis of the data.

Results
An overall HIV prevalence of 29.27% (95% CI: 24.78–34.09) was found. Female TB patients had higher odds of HIV infection (OR 1.91, 95% CI: 1.03–3.55) while patients with the highest education had the least odds of HIV infection [OR 0.08, 95% CI: 0.01–0.56].

Conclusion
Evidence of a rising tide of HIV infection in TB patients was found, in particular among single middle-aged women with low education. Further research also needs to be conducted to provide more insight into the epidemiology of co-infection in order to better address the dual burden of HIV and TB among tuberculosis patients in Nigeria.