Background: The Commission of the European Communities has published guidelines to be used as a gold standard for quality assessment of diagnostic radiographic images. Image quality and radiation dose must be monitored and optimally balanced for diagnostic purposes on patients. The objective of the current study was to assess intra- and inter-observer reproducibility in less experienced observers using the proposed European Guidelines on Quality Criteria for Diagnostic Radiographic Images in a quality assessment of lumbar spine radiographs in primary chiropractic practice in Denmark. Methods: Two observers initially evaluated lumbar spine radiographs randomly selected from fifty chiropractic clinics, all connected to the national PACS server (KirPACS) in Denmark. All evaluations were performed twice by both observers using a four-week interval and for compliance with the European Quality Criteria for Diagnostic Radiographic Images. Inter- and intra-observer reproducibility was calculated using kappa statistics. In the interpretation of the kappa coefficient, the standards for strength of agreement reported by Landis and Koch were followed. Results: The strength of the inter-observer agreement of general image quality at baseline ranged from moderate agreement (k = 0.47) to substantial agreement (k = 0.68). After four weeks, the inter-observer agreement still ranged from moderate agreement (k = 0.59) to substantial agreement (k = 0.71), but with increased agreement for both kappa coefficients. In relation to intra-observer agreement of general image quality, the strength for observer A ranged from moderate (k = 0.58) to substantial (k = 0.72) and the strength for observer B overall was substantial (k = 0.63-0.75). Conclusion: The European Guidelines on Quality Criteria for Diagnostic Radiographic Images are considered a gold-standard and used in a method for quality assurance within the Danish chiropractic profession. The inter-rater and intra-rater agreements in this study, using the CEC-criteria, were found mostly acceptable. With appropriate attention to clear understanding of the individual criteria and sufficient training, this method is found to be reliable, even using less experienced observers, to carry out Diagnostic Radiographic Image Quality-assurance in primary care settings.