Free Voluntary Counseling and Testing HIV (VCT) was implemented in over 63 provinces in the last many years. This study was conducted to evaluate the use of VCT service among commercial sex worker (CSW) and to estimate the factors affecting to use of VCT service in Can Tho city. Two-cluster study was conducted from August to September, 2011 to interview 374 CSWs in Can Tho. The results showed that the proportion CSWs usually meet the clients in restaurant! beer bar, in Karaoke bar, in massage parlor and in the street/park were 44.3 percent, 15.1 percent, 14.7 percent and 10.7 percent, respectively. 4.5 percent of CSW in Can Tho was injected drug in the past month. The proportion ofCSW waiting the clients in street/park, in hotel/guest house/motel, and through mobile phone used drug were 22.5 percent, 18.2 percent and 12.5 percent, respectively. Logistic regression analysis showed that CSWs injected in the past month had likely 3.8 time visiting VCT than the CSWs who did not inject. Behavior-change communication need focus not only injecting drug people having the risk of HIV transmission but also all CSWs having the risk of HIV transmission and need to visit VCT.