Abstract: Objective To evaluate the effectiveness of free highly active anti-retroviral therapy (HAART) for HIV/AIDS infected unlicensed prostitutes and patients in Dehong Prefecture. Methods Investigation was done on HIV/AIDS infected unlicensed prostitutes and patients in Dehong Prefecture who began to receive HAART during the period from July 2004 to Sept 2014. The change of CD₄⁺ T lymphocyte count and HIV viral load before and after treatment were retrospectively analyzed with SPSS software to examine their virological and immunological responses to HAART. Results The total of 61 unlicensed prostitutes and patients received HAART, their mean age being 26.2±8.7 and those unmarried accounting for 42.6%. At the baseline, 78.7% with CD₄⁺ T lymphocyte count <350/mm³, 21.3% were ≥ 350/mm³ and the mean CD₄⁺T lymphocyte count was (264.2±190.2)/mm³ at baseline, and was (548.4±331.9)/mm³ for patients after treatment. The differential mean value was (284.2±281.4)/mm³. Compared with those at the baseline, CD₄⁺ T lymphocyte increased significantly at different stages of treating for one year, two years, three years and more (P<0.05). There was also significant difference between different treatment time group (χ²=4.475, P=0.007). The 61 patients received viral load test, of whom 56 (91.8%) had irological suppression, with viral loads under the lowest limit. There was significant difference between different treatment time (χ²=6.746, P=0.035) and with the extension of treatment time. The success rate of virologic suppression gradually increased (χ²=6.273, P=0.012). There were 5 patinets done with drug resistance surveillance, among them one was found HIV-resistant, but after changing drugs used, the level of viral loads remained undetectable. Conclusion The investigation proved that both virological and immunological responses to HAART were well achieved and fairly effective for HIV/AIDS unlicensed prostitutes and patients in Dehong Prefecture.