Neck pain is one of the most prevalent musculoskeletal diseases which results in considerable pain and disability, and has a great impact on individual level, as well as on health-care system, and overall society. Causes of neck pain are different, and prevailing aetiology are mechanical reasons associated with degenerative changes of cervical spine. We are witnessing various diagnostic and therapeutic approaches for these patients. The Croatian Society for Vertebrology of the Croatian Medical Association is presenting a comprehensive narrative review and guidelines for the diagnosis and treatment of neck pain, focusing on the most prevalent causes. The guidelines are the result of consensus of experts of different background, based on the best available evidence. This part (Part 1) relates to diagnosis, while the complementary part (Part 2) relates to treatment. For the diagnostic part (Part 1) the guidelines encompass: clinical features and evaluation (including questionnaires), laboratory tests, imaging, neurophysiology tests, and minimally invasive diagnostic procedures. The management part (Part 2) includes: pharmacology treatment, physical exercise, traction, manual therapies, physical therapy modalities, orthotics, minimally invasive therapeutic interventions, surgical treatment, rehabilitation after surgical procedures, and psychiatric approach. These are the first Croatian guidelines for neck pain intended in the first place for the physicians’ professional community.