OBJECTIVE To compare caries status assessment of posterior teeth of young Chinese adults by using clinical examination alone and with the supplemental use of bitewing radiographs. METHODS Two calibrated dentists examined the posterior teeth of 200 Chinese university students (aged 18-24 years) using dental mirrors and probes under optimal lighting. Caries was diagnosed by visual detection of carious cavities. Duplicate examinations were performed to monitor intra- and inter-examiner variations. Bitewing radiographs were taken and examined by an independent dentist. Caries was recorded when a lesion extended into dentine. RESULTS Among the 3,162 posterior teeth examined, 113 were detected with caries. More than one third (35.4%) of the caries found in the posterior teeth was not detected from reading the radiographs but was detected by clinical examination. About half (51.4%) of the caries was found on the bitewing radiographs only, leaving 13.2% being detected by using either method. With the supplement of bitewing radiographs, there was a 105% increase in the number of carious lesions detected. This leads to a correction factor of 1.13 for adjustment of the mean DMFT score obtained from conducting clinical examinations alone. CONCLUSIONS Due to the significant number of clinically undetected carious cavities in these young Chinese adults who live in a community with water fluoridation, it may be advisable to use a correction factor to adjust the caries experience obtained from epidemiological surveys when bitewing radiographs are not available.