Insulin resistance is a prevalent condition commonly associated with unhealthy lifestyles. It affects several metabolic pathways, increasing risk of abnormalities at different organ levels. Thus, diverse medical specialties should be involved in its diagnosis and treatment. With the purpose of unifying criteria about this condition, a scientific-based consensus was elaborated. A questionnaire including the most important topics such as cardio-metabolic risk, non-alcoholic fatty liver disease and polycystic ovary syndrome, was designed and sent to national experts. When no agreement among them was achieved, the Delphi methodology was applied. The main conclusions reached are that clinical findings are critical for the diagnosis of insulin resistance, not being necessary blood testing. Acquisition of a healthy lifestyle is the most important therapeutic tool. Insulin-sensitizing drugs should be prescribed to individuals at high risk of disease according to clinically validated outcomes. There are specific recommendations for pregnant women, children, adolescents and older people.