Purpose of this reasearch is to evaluate clinical perfomance of electronic device CarieScan Pro and ICDAS method in caries detection using histological gold standard. The study was made on occlusal surfaces of 40 human permanent teeth which were indicated for extraction because of tooth erruption problems, orthodontic and parodontic reasons. A trained examiner assessed 72 measurement points on occlusal surfaces using ICDAS criteria and CarieScan Pro device. After a tooth extraction, measurements were repeated and the samples were histologically evaluated. The results were statistically analyzed with Chi-square test and Interclasse correlation test, with significance level p<0.05. The sensitivity, specificity and accuracy for these caries detection methods were calculated. The repeatibility of measurements for CarieScan Pro device in vivo (Interclass Correlation Coefficient) was 0.848, and in vitro 0.888. The statistically significant difference was found between in vivo and in vitro measurements. The strongest correlation between the examined method and histological validation expressed by Cohen’s Kappa is achieved in the visual ICDAS method (0.613). CarieScan Pro in vivo had negative correlation (-0.037) and in vitro showed somewhat better result (0.199). The most accurate was ICDAS method (95.9%), while in vivo CarieScan Pro had the accuracy of 86.1% and in vitro of 87.5%. Based on this research, ICDAS method is more reliable in caries detection than the electronic device. The correlation with histological validation is higher with the ICDAS method, as well as the accuracy and sensitivity of te method in relation to CarieScan Pro device.