Our objective was to develop clinical guidelines based on the best clinical evidence to help the staff of medical setting of all levels (first, second and third medical attention levels) to provide evidence based care and diagnosis of hypothyroidism in adults nationwide. The guidelines were built using structured and relevant clinical questions. A strategy was developed to identify the main clinical guidelines for hypothyroidism in adult patient. The working group selected six documents. For aspects not considered in those documents, structured searches using Pubmed, Medical Disability Advisor, and Cochrane Library Plus were done. The results were qualified according its level of evidence and grade of recommendation. The diagnosis of hypothyroidism should be done precisely and without delay. Specialized care should be used rationally, using primary care units as the main resource for the treatment of hypothyroidism. This is the reason why the first primary care physicians should understand and apply a guideline for the diagnosis and treatment of hypothyroidism in adulthood.