The erectil dysfunction is a common disorder in diabetic patients resulting from neurological, arterial and endocrine factors. This paper presents an eco-doppler evaluation of the arterial factor in 88 diabetics: 17 controlled with diet, 38 with oral anti-diabetic agents and 33 with insulin. Age, ranging from 23 to 70 years old, was similar in subjects controlled with diet (55.6 +/- 6.4) or anti-diabetic agents (57.6 +/- 7.9), but greater in insulin-treated subjects (46.8 +/- 10.5) (p < 0.01). Fifty-six subjects (63.6%) has nocturnal and 43 (48.9%) diurnal erections, 45 (51.1%) achieving penetration. There was 65 (73.9%) smokers, 28 (31.8%) hypertensives, and 24 (27.3%) reported stress. A baseline evaluation was performed in all cases, in 87 after I.I.C (papaverin 26 and PgL1 61), full erection being achieved in 18 cases, non-rigid erection in 15, tumescence in 50 and with no response in 4. No differences were seen by type of diabetes. The variance analysis showed no differences in the flow speed indicators among the three groups, both at rest and after I.I.C., the sample being therefore homogeneous, superposable to arterial dysfunctions and significantly lower than those of the control group (p < 0.01). We conclude that diabetes induces arterial changes which are superposable to those caused by other vascular risk factors and independent for the type of diabetes.