Aims. To characterize hypogonadism in male persons with diabetes mellitus. Patients and Methods. 184 consecutive male persons with diabetes were studied. Besides the usual care, total testosterone (TT), estradiol (E2), FSH, and LH were measured in the last appointment and in 40 patients, also in the next two appointments. Statistical analysis compared groups and explored factors for TT and LH levels. Results. TT levels were stable and highly correlated (r > 0.750,
p
<
0.001
) over a 6–12-month period. 20% of the patients presented secondary hypogonadism (SH) and 18% presented primary hypogonadism (PH). SH was inversely related to HbA1 (partial r (rp) = 0.229,
p
<
0.005
), while PH was directly related to age (r = 0.356,
p
<
0.001
). TT levels were reduced independently by metformin (364 ± 160 vs. 431 ± 242 ng/dL, t = 2.241,
p
<
0.05
) and statins (359 ± 156 vs. 424 ± 230 ng/dl, t = 2.224,
p
<
0.05
). TT levels were inversely related to microvascular disease (rp = −0.169,
p
<
0.05
). Discussion. TT levels were stable over time and hypogonadism was common. SH, generally clinically, is related to the diabetic state, while PH, generally subclinically, is an age-dependent process unrelated to diabetes. Low TT levels were related to older age, poor metabolic control, metformin and statins use, and microvascular disease.