A study was conducted to describe the genetic diversity of hepatitis C virus (HCV) in a population of positive blood donors from throughout Indonesia. Repeat analysis by reverse transcription-polymerase chain reaction (RT-PCR) of 102 anti-HCV positive samples showed that 67 gave HCV-specific positive signals by the PCR for the 5'-untranslated genomic region of HCV. Further genotypic analysis on 64 HCV RNA-positive samples indicated that 57 belonged to the following individual genotypes: 1a, 1b, 2a, 2b, and 3b. The predominant HCV genotypes in this donor population were 1b (57.8%), 2a (17.2%), and 3b (10.9%). The core sequences of the 4 indeterminate samples when aligned with published sequences of various HCV genotypes showed a range of homology from 16.16% to 78.67%. Comparative analysis of genotypic representation from other anti-HCV-positive study populations, including polytransfused pediatric and adult renal dialysis groups, is now being carried out to determine the potential genotypic association with mechanistic HCV spread.