Women especially the commercial sexual workers (CSW's) relatively more frequent saferred from sexual transmitted diseases (STD's). Recently, transmission of STD's become wide not only among the high risk groups such as commercial sexual workers, but also the commumty that were grouped as the low risk group (National Household Health Survey). The AIDS cases, one of the STD's, increase sharply during the last two years. In Surabaya municipality, the cases were increase from 9 cases in 2000 to become 103 cases in 2002 (Kompas, Wednesday. 14 May 2003, page 1). The Prevention and controlled of HIV/AIDS was the one of priority in the prevention and controlled of diseases program in Indonesia, because of not only the cases that became numerous, but also it was the global commitment. The aim of the study was to explore the knowledge on STD's among CSW's and the prevention and seeking care behavior against the STD's among CSW's m Dolly and Jarak, Surabaya. The systematic random sampling was applied in selecting the sample. The population was the CSW's in Dolly and Jarak, Surabaya. The total number of respondent was 230, selected from about 1.900 CSW's in the localization of Dolly and Jarak. The result showed that about half of the respondents was relatively young (less than 25 year), widow and working as professional CSW's during one year or less. Most of the respondents knew about STD's such as: Syphilis, HIV/AIDS, Gonorrhea and Flour albus, but only a few knew other symptoms and or STD's such as Clamedia. Nearly all of respondents did some kind of prevention from STDs' transmission, such as drinking the traditional medicine or remedy without prescription, although only half of them felt that the prevention was working. More than a half of the sample ever suffered from STD's, and a few of them still gave services to their client during suffering the diseases. Most of CSW's who suffered from STD's sought care from health personnel's. A half of them received health education from the health provider especially about obeying in taking medicine, use condom, not giving services to client during illness and dangerous of STD's. In general the respondents felt satisfied with services from health personnel's, in terms of politeness, waiting lime, facility of services and the result of remedy.