This observational cross-sectional study aims to determine pain phenotypes in individuals with chronic low back pain (CLBP). Participants will be classified according to a mechanism-based clinical pain phenotyping algorithm as having nociceptive, neuropathic, nociplastic, or mixed pain. Clinical history, quantitative sensory assessment, pain characteristics and distribution, central sensitization-related symptoms, disability, health-related quality of life, and pain catastrophizing will be assessed. In addition, the intra-rater and inter-rater reliability of the pain phenotyping algorithm will be investigated, and the clinical characteristics of different pain phenotypes will be compared.