BACKGROUND: The Danish Authorisation Act sets out the chiropractic scope of practice. Under this legislation the scope of practice is diagnostics, prevention and treatment of biomechanical disorders of the spine, pelvis and extremities. Despite this and an international movement toward a scientifically active, evidence-based profession with a focus on treatment of musculoskeletal disorders, a large proportion of chiropractors still offer treatment of non-musculoskeletal disorders. This study aimed to investigate the content and characteristics of website claims by chiropractors in Denmark on non-musculoskeletal conditions and to assess whether these were aligned with the Danish Authorisation Act of the chiropractic scope of practice. METHODS: In this cross-sectional study data on a representative sample were collected from chiropractic clinic websites in Denmark. Information on non-musculoskeletal conditions from the websites was categorised. For each non-musculoskeletal condition, it was noted whether a clarifying explanation justifying the presence of the diagnosis was available and what it said. These explanations were assessed and categorised according to agreement or disagreement with the chiropractic scope of practice as defined by the Danish Authorisation Act. In addition, data on geographic location, clinic size, reimbursement coverage, country of education and special clinical focus (children, athletes, etc) were collected. Differences in characteristics of the clinics and the frequency of reporting non-musculoskeletal conditions were tested using Pearson's chi-squared or Fisher's exact test. RESULTS: A geographically stratified, random sample of 139 (57%) websites was included from chiropractic clinics in Denmark. In total, 36 (26%) of the sampled websites mentioned conditions of non-musculoskeletal origin that was not accompanied by a clarifying explanation in agreement with the chiropractic scope of practice. A positive association between advertising infant or children's care and advertising treatment for non-musculoskeletal disorders (without adequate explanation) was observed. CONCLUSIONS: A total of 36 (26%) of the sampled chiropractic websites in Denmark mentioned diagnoses or symptoms of non-musculoskeletal origin on their websites without presenting an adequate clarifying explanation in agreement with the chiropractic scope of practice as defined by the Danish Authorisation Act. This could be misleading for patients seeking care for non-musculoskeletal conditions and consequently lead to inappropriate treatment.