To understand the current epidemic situation and high risk factors of human immunodeficiency virus (HIV) infection among paid blood donors living in Shandong provincial China Comprehensive Response (CARES) Project Areas. All residents between 20 to 60 years old were selected from one or several counties in August 2003. There were 19 HIV(+) infections among 661 subjects interviewed. HIV prevalence rate among paid blood donors was higher (3.98%) than that of others (0.48%) while HIV prevalence rate was higher in plasma donors (7.24%) than that in both plasma and full blood donors (2.90%). There was no infections identified in full blood donors. Donors who donated blood during 1994 - 1995 had a higher prevalence rate (7.07%) than those who started donation after 1995 and those began donation before 1993 (0.99%). The rate of condom use was lower among paid blood donors (13.72%) than that of others. There was a lower rate of voluntary HIV testing among paid blood donors than that of others. The main high risk population of HIV infection were paid donors in CARES Project Areas, whose risk factor was plasma donation and were infected mainly before 1995. Both the rate of condom use and HIV testing were all very low, indicating that they knew little on HIV/AIDS and paid less attention to self-proctection. It is necessary to enhance HIV/AIDS health education and behavior intervention on paid blood donors.