Abstract. Chedad AW, Hammou MA, Chelghoum H, Chedad A, Amara OO, El Bouhissi M, Dahmani W, Sadine SE. 2022. Diversity and distribution pattern of scorpions from the Ouarsenis massif of Tissemsilt, North-West Algeria. Biodiversitas 23: 2444-2450. Ecological barriers such as mountains are important factors leading to fragmentation of the range of different species and the important cause of vicariance events. Ouarsenis massif (Tissemsilt, North-West Algeria) is an important protected Park. This paper presents a preliminary study of scorpion diversity and assesses this biodiversity change in this Mountain range along a gradient of many ecological descriptors, including elevation, vegetation cover, slope, and soil types. During 2020 and 2021, we sampled 179 specimens of scorpions by direct hunting from the eight biotopes in Ouarsenis massif. Only adult individuals were used for identification after being killed and kept in 70% alcohol. Based on morphological criteria, we identified eight species distributed in two genera and two families. The family Buthidae was represented by five species with the highest relative abundance (RA) was Buthus tunetanus (RA: 47.49%). Furthermore, the family Scorpionidae was represented by three species with the highest RA was Scorpio maurus (RA: 25.14%). The Shannon index (H’: 2.71 bits) indicated that Ouarsenis massif region had a high level of scorpion diversity and the value of evenness (E: 0.90) reflected the high equilibrium between the effectiveness of sampled species. The main determinant descriptor of scorpion distribution was the elevation and soil types, while the vegetation cover could be considered an ancillary factor.