There is ample scientific evidence that a person with an untreated STI, particularly thoserninducing ulcers or discharge, is at an increased risk of passing on or acquiring HIV duringrnsexual intercourse. HIV CT for STI cases is thus an important tool in the public healthrnresponse to HIV/AIDS. A descriptive, cross-sectional study, involving 422 STI cases, wasrnconducted to assess factors affecting willingness towards HIV CT among patients presentingrnwith the conventional STIs in Addis Ababa, from December 2006 to April 2007. STI patientsrnwere consecutively selected during an outpatient visit in ten government health centers whichrnwere purposively selected mainly on the basis of their high STI case load. A pre-tested,rninterviewer administered, structured questionnaire was applied for data collection. OR withrn95% CI was used to measure the degree of association between associated factors andrnwillingness towards HIV CT and, logistic regression analysis was done to identify predictorsrnof willingness towards HIV CT.rnOverall, 73.9% of STI patients said that they would be willing to undergo HIV CT at the timernor 3 months after their STI diagnosis. Furthermore, 97.4% and 71.8% of STI patients hadrnheard about HIV/AIDS and STIs, respectively. Nearly 93% of STI patients knew at least onernprevention method, and 61.2% identified all the three major methods for preventingrnHIV/AIDS. Overall, 43.8% of the STI patients had at least one misconception, and 38% hadrncomprehensive knowledge about HIV/AIDS. Moreover, 74% of STI patients said that theyrnnever used condoms during the previous 12 months. The proportion of those who reportedrnever had HIV test was 45%. More than half (61.5%) of the STI patients reported â€˜no or lowrnchanceâ€™ of acquiring HIV and the main reason they gave was they trusted their partner. One orrnmore stigmatizing attitudes also prevailed in 33.3% of the STI patients. Ever tested for HIV,rnbeing in the age group of 15-34 years, and perceiving small or moderate chance of contractingrnthe HIV infection were found out to be significantly associated with willingness towards HIVrnCT.rnThe findings of this study indicated the need for promotion and expansion of sustainablernprovider initiated HIV CT with subsequent follow up to STI patients as part of a continuum ofrnservices and support, and intensive patient-centered risk reduction counseling for STI casesrnduring the initial visit to health care facilities.