Codependency is defined as a dysfunctional pattern of relating to others, present in relatives of those with a substance use disorder or other chronic disease. It is characterized by emotional dependence, extreme focus in the other person, and self-neglect. Aim: to present results of the process of development and validation of a new measure to evaluate codependency. Method: The Argentinean codependency scale was administered to a convenience sample of 347 subjects between 15 and 80 years, in Mar del Plata. AFE was used (main axes extraction method). The number of factors was determined by parallel analysis. Internal consistency was assessed using Cronbach's Alpha. Item level statistics were also estimated. Results: Three factors were obtained. The internal consistency of the total scale and the three subscales was satisfactory. Relatives of alcohol or drugs dependents and of people with other chronic diseases had scores significantly higher in the codependency measure than those in the general population group.