OBJECTIVE: To investigate the frequency of transfusion transmitted virus (TTV) infection in healthy blood donors in Hangzhou area and the mutation of TTV genomic fragment. METHODS DNA in serum samples of 203 healthy donors was extracted by phenol-chloroform method to detect TTV by semi-nested polymerase chain reaction and nucleotide sequences of partial amplification products were determined after T-A cloning. RESULTS TTV infection rate in 203 cases of blood donors in Hangzhou area was 15.3%. The homology of the amplified products of partial TTV positive samples compared with thereported nucleotide and putative amino acid sequences of TTV TA278 were 63.51% approximate, equals 67.12% and 59.46% approximate, equals 66.22% respectively. CONCLUSIONS TTV infection rate in the blood donors in Hangzhou is relatively high. The TTV infecting blood donors in the area may be a kind of novel genotype.