The JC polyomavirus (JCV) is ubiquitous in humans, infecting children asymptomatically, then persisting in renal tissue. Since JCV DNA can be readily isolated from urine, it should be a useful tool with which to study the evolution of DNA viruses in humans. We showed that JCV DNA from the urine of Japanese, Taiwanese, Dutch and German patients can be classified into A and B types, based upon restriction fragment length polymorphisms (RFLPs). This work was extended in the present study. We established multiple JCV DNA clones from the UK, Spain, Italy, Sweden, South Korea, People's Republic of China, Malaysia, Indonesia, Mongolia, India, Sri Lanka, Saudi Arabia, Ethiopia, Kenya, Zambia, South Africa and Ghana. Using type-specific RFLPs, most clones except the four clones from Ghana were classified as either type A or B. We constructed a molecular phylogenetic tree for the Ghanaian clones and several representative type A and B clones. According to the phylogenetic tree, the Ghanaian clones constituted a major new group, tentatively named type C. From the findings presented here and elsewhere, the following conclusions were drawn: (i) type A is prevalent only in Europe; (ii) type B is found mainly in Asia and Africa; and (iii) type C is localized to part of Africa. Our findings should help to clarify how JCV evolved in humans.