Human T-cell lymphotropic virus (HTLV) is a retrovirus transmitted through breastfeeding, sexual contact, blood transfusion and injecting drug use. HTLV is endemic in the Caribbean and parts of Africa, Japan and South America, with isolated foci in other areas. Infection is life-long. Less than 5% of those infected progress to one of the HTLV-related diseases, but these are debilitating and often fatal. Laboratory reports of new HTLV diagnoses are followed up through clinicians to establish information such as probable country of infection, country of birth, clinical details and reason for test. Clinician reports are also received for HTLV-infected blood donors identified by the National Blood Service. Seventy-seven individuals newly diagnosed with HTLV infection in 2002 were reported to the Communicable Disease Surveillance Centre (CDSC) by June 2003. Thirty-three (43%) were male, and 44 (57%) female, with median ages at diagnosis of 58.5 and 50.1 years respectively. Seventy-three (95%) individuals were HTLV-I positive and three HTLV-II positive, with one remaining untyped. For 52 of the 77 infections, clinician reports were received. Where ethnicity was reported (48), 30 (63%) were Black Caribbean, 12 (25%) White, and the remainder (6) of other ethnicities. Probable route of infection was reported for 31 individuals: nine (29%) were probably infected heterosexually, seven (23%) through mother-to-child transmission, 12 (40%) through either route, two through blood transfusion, and one through injecting drug use (HTLV-II positive). Where probable country of infection was reported (31), 14 (45%) were probably infected in the UK, 13 (42%) in the Caribbean, and four elsewhere. Where reported (50), reason for test was: symptoms for 19 (38%) individuals, blood donation for 21 (42%), and the remainder for other reasons. Numbers of new HTLV diagnoses were relatively high in 2002, and the characteristics of patients and clinical presentations differed from previous years, mainly due to the introduction of blood donor testing for anti-HTLV. Beyond 2004, the number of HTLV-infected individuals detected through blood donation is expected to decline. While numbers of individuals affected are small compared to many other diseases, the infection is chronic and untreatable, and it is important that adequate standards of diagnosis, prevention, care and support are provided, and surveillance maintained.