In this paper, the identification of a new relevant control model for type 1 diabetic patients is developed, which allows to compute the tools of the functional insulin therapy directly from its parameters. Also, this new model possesses equilibriums according to the physiological behavior, i.e. i) without insulin, the glycemia raises indefinitely, ii) with basal insulin, the glycemia is maintained at its actual value (it does not go to the basal levels, as it is stated by the standard models), and iii) with a carbohydrate input, the glycemia raises and remains at a high value if no insulin is administered. For the identification stage, different structures of the model are analyzed with different identification algorithms in order to select the best structure and algorithm (which minimizes the fit error). A set of data collected during 3 days from real and virtual patients (from the UVA/Padova simulator) was used to identify the model. The fit obtained was 20% y 70% for real and virtual patients, respectively. The conclusions of this study are i) the proposed model even its simplicity can be used to represent diabetic patients and ii) this promotes its potential application to the so-called artificial pancreas in the design of control strategies, as model predictive control.