Although not as frequent as sciatica, cruralgia remains one of the most frequent reasons why people consult a neurosurgeon. It should be kept in mind, however, that every anterior leg pain is not cruralgia and thus several diagnoses must be discarded, such as of musculoskeletal diseases of hip, pelvis and femur. In the last years of the 19th century, André Léri, a French neurologist, described Leri's sign as it is used widely even today in everyday clinical practice. We studied retrospectively files of those patients who were seen in Neurosurgery by the authors for L3 and L4 nerve root compression to evaluate the reliability and accuracy of this sign. Between October 1998 and September 2017, 38,654 patients were examined in our department of Neurosurgery. Among them, 1698 patients presented pain as cruralgia and meralgia. In total, 1545 patients were included in the study. The data analysis showed that the sensitivity of LS was 0.9333 and the specificity 0.7974. The results of the study show a reliable diagnostic accuracy of Leri's sign.