Objective. To assess whether radiographic examinations are necessary to evaluate (trends in) the prevalence of caries, a summary was made of data from epidemiological studies comparing the results of clinical and radiographic examinations in young populations. Method. A literature search yielded seven studies that met the inclusion criteria. A two-by-two table of radiographic versus clinical data was constructed for each study. These data were used to assess the radiographic and clinical prevalences and to find a conversion factor to calculate the total prevalence from the clinical prevalence. Results. In the approximal surfaces the radiographic prevalence was considerably higher than the clinical prevalence. The conversion factors to calculate the total prevalence from the clinical prevalence varied considerably across studies. In the occlusal surfaces the radiographic and clinical prevalences were about similar, but extra lesions were detected with both methods. Conclusion. To study trends in the prevalence of caries, radiographic examinations are not necessary but to assess the prevalence of caries they do have unknown additional value. To obtain a valid conversion factor for relevant patient categories, agreement between the results of radiographic and clinical examinations should be investigated in sub samples of epidemiological studies.