While much is known about the molecular epidemiology of HIV infection in India, surprisingly little is known about the situation in neighboring Pakistan. To what extent the major HIV subtypes in Pakistan resemble those in India need clarification. Through a collaborative arrangement with Dr. Sten Vermund, of the Division of Geographic Medicine at the University of Alabama at Birmingham, and Dr. Muhammad Ashraf Memon, Director of the Sindh AIDS Control Programme in Karachi, the expert assistance of the RCMI-supported RRL has been requested to investigate this urgent issue. After a week-long delay, buffy coat blood samples from 10 HIV-infected Pakistani (including a 6-year old boy with hemophilia), originally shipped on dry ice, arrived in a thoroughly thawed condition in the RRL. DNA was, nevertheless, extracted from these blood samples and HIV env gene sequences were amplified by PCR. Subtypes A, C and D were found (Table 2). The presumed mode of HIV acquisition was by heterosexual intercourse in all but one of the study participants. Moreover, all but one reported travel outside of Pakistan. Travel was primarily to Dubai and the United Arab Emirates (UAE), where these men were employed as overseas contract workers (OSC); the exception was a 6-year old boy with hemophilia who had received many blood transfusions. Phylogenetic analysis revealed that the HIV subtype C strains from Pakistan were very closely related to those found in nearby India. The multiclade nature of HIV infection in Pakistan has not been previously reported. Both the gag and nef genes of these HIV strains are currently being sequenced and analyzed. Thereafter, a manuscript will be submitted for publication to AIDS Research and Human Retroviruses.