Dental erosion is a common problem in modern dental practice. It is related to the action of exogenous and endogenous acids on the surface of the teeth, or from chelation in the absence of dental plaque. Erosion leads to the irreversible loss of dental hard tissues – enamel and dentine, so its early diagnosis is particularly important if the progression of lesions is to be prevented. Diagnosis of the initial stages of erosion is difficult since manifest changes in the characteristics and morphology of the enamel take time to develop. Erosion indices can help dentists diagnose and monitor the treatment process, as well as determine the progression of erosion. Numerous erosion indices are described in the literature, which leads to problems when the results of clinical and epidemiological studies are compared. The ideal index should not only determine the presence of an erosive lesion, but should also assess its severity and progression. Furthermore, it should be repeatable and easy to interpret. Designing such an ideal index is challenging, and further studies are being carried out to standardize the terminology and strategy of dental erosion management. The aim of the article is to review and present the dental erosion indices currently used in the diagnosis of erosive lesions of dental hard tissues.