This review describes several types of genetic polymorphism, which have recently been identified in human urine in our laboratory, and have also been found in other human body fluids such as blood, saliva and semen. These include uropepsinogen, ribonuclease, deoxyribonuclease I (DNase I), deoxyribonuclease II (DNase II), 43-kDa glycoprotein, alpha-L-fucosidase, glutamate pyruvate transaminase, alpha-2-HS-glycoprotein, transferrin and vitamin D-binding protein. Several substances can be detected more easily in urine than in plasma. The concentrations of uropepsinogen, DNase I and DNase II in blood plasma are too low for analysis, whereas those in urine are high enough for easy typing. In practice, DNase I-polymorphism is one of the most useful genetic markers for practical purposes, because of its higher content in various body fluids including urine, a well-balanced gene frequency, and its easy and accurate detectability. Furthermore, several genetic markers previously identified in blood and/or other forensic samples can be phenotyped reproducibly and easily from the corresponding urine samples. Thus, urine, in addition to the convenience and non-invasive nature of its collection, is by no means inferior to blood as a sample source for typing in the field of forensic science. Biochemical and serological typing of genetic polymorphisms present in human urine could offer useful information to practising forensic biologists for forensic individualization of urine samples.