We conducted a mail survey of Thai physicians involved in obstetric care to assess attitudes and practices regarding zidovudine use during pregnancy and willingness to provide care for HIV-infected women in 1999. Of 845 respondents, 57% reported using perinatal zidovudine prophylaxis, an increase from 20% reported in 1997. Highest failure-to-use rates (52%) were among the respondents from Central and Southern Thailand and lowest failure rate was among those from the North (37%). Predictors of failure to use zidovudine in a multivariable logistic regression analysis were not knowing a source from which to obtain zidovudine (odds ratio [OR]=3.1), working in smaller hospitals (district/provincial/private hospitals) (OR=2.0), being from Eastern/Central/Southern Thailand (OR=1.4), unwillingness to perform caesarean section delivery on a HIV-positive women (OR=1.8), having provided antenatal care to fewer than 100 women in 1998 (OR=1.7), and unfamiliarity with Pediatric AIDS Clinical Trial Group 076 protocol (OR=2.9). A number of respondents described themselves as unwilling to perform pelvic examinations (15%), vaginal delivery (29%), or caesarean sections (37%) on HIV-infected pregnant women. About 39% of the respondents advocated elective terminations of pregnancy for HIV-infected women. Our survey indicates an increasing willingness of Thai physicians to use antiretroviral therapy to prevent mother-to-child HIV transmission and to provide obstetric care to HIV-infected women. However, availability and affordability remained major barriers to more widespread antiretroviral use in 1999.