We performed a retrospective study in 72 autopsies of diabetic patients (DMP) selected out of 2,239 adult autopsies, comprehending the period between 1966 to 1982. In order to analyse the possible Diabetic Cardiomyopathy, the DMP were divided into 8 groups according to the presence or the absence of Myocardial Fibrosis (MF) and Congestive Heart Failure (CHF). The Diabetes Mellitus (DM) incidence according to the race, sex, age and the presence of Kimmestiel-Wilson (KW) were in agreement with the literature data. The majority of the deaths occurred after the sixth-decade and we did not find any DMP with Malignant Hypertension. Hypertension and Coronary Artery Disease (CAD) increased the frequency of anatomical cardiac alterations, as follows: 1. MF was more associated with CAD, 2. Hypertension was more frequent in DMP with KW in the nodular form; 3. Hypertension increased the frequency of left ventricular hypertrophy; 4. Myocardial Infarction occurred in the absence of occlusive vascular phenomena. The Myocardial Fibrosis (MF) observed in DMP without ACD and without hypertension may be final anatomic demonstration of a gradual metabolic-functional process, and not the basic mechanism of the CHF in the possible Diabetic Cardiomyopathy.