Phenotypes of inter-alpha-trypsin-inhibitor (ITI) have been determined by isoelectric foCUSing on polyacryl-amide gels followed by immunofixation. The phenotype fre-quencies of ITI in the Han population in Chengdu. P. R. China have been investigated using this method. In addition, family studies have been conducted in 21 families. The re-suits show that ITI iS polymorphic in the Han population in Chengdu. China. The allele frequencies are as follows: ITI*1=0.5763. ITl*2=0.4107. ITl*3=0.0130. ITI is thus a new and promising genetic marker that can be used in the field of forensic haematogenetics.