Healthcare workers who carry out exposure-prone procedures are theoretically at increased risk of acquiring blood-borne virus infections. GB virus C (GBV-C) is a recently described blood-borne virus that is related distantly to hepatitis C virus. The occupational risk of GBV-C infection to healthcare workers is unknown. This study collected detailed occupational and personal risk data in parallel with a blood specimen, to establish the prevalence and determinants of GBV-C infection among dental healthcare workers. The presence of GBV-C antibodies was detected using commercially available ELISA; GBV-C RNA was detected by nested PCR using primers from the conserved 5′ noncoding region. The overall prevalence of GBV-C antibodies among the study population was 11.1% (98/880, 95% confidence interval [CI], 9.1–13.4%) and 4.6% were positive for GBV-C RNA (46/879, 95% CI, 2.5–5.1%), resulting in a cumulative prevalence of 15.7%. These figures are similar to those described in other populations. There was no significant difference in lifetime exposure to GBV-C between dentists (17.7%) and dental nurses/hygienists (14.3%). Significantly more dental nurses/hygienists aged 16–30 years had been exposed to GBV-C compared to dentists of the same age (χ2 = 13.75; P < 0.001). Conversely, significantly more dentists 46 years or older had evidence of exposure to GBV-C compared to dental nurses/hygienists (χ2 = 6.79; P = 0.009). The high prevalence of GBV-C infection did not seem to be related to past parenteral exposure, and the data suggest that sexual transmission, rather than occupational transmission, was a more important route for GBV-C infection among this population. J. Med. Virol. 70:150–155, 2003. © 2003 Wiley-Liss, Inc.