The aim of this paper is to describe metabolic and endocrine alterations in the male, partners of infertile couples. One hundred and six consecutive men were taken in order to analyze their serum samples. Each serum sample was analyzed by duplicate for luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), free-testosterone (T), 17 alpha-hydroxyprogesterone (17OHP), androstenedione (A), dehydroepiandrosterone-sulphate (DHEA-S), prolactin (PRL), insulin, glucose, total cholesterol and triclylcerides. The data analysis evidenced different metabolic or endocrine alterations in the group. A dysplipidemia incidence of 65% was found (isolated hypercholesterolemia, isolated triglyceridemia or both), where 80% of these patients were younger than 40 years. There was no correlation with obesity, overweight any endocrine alteration and the type of sperm alterations. There was a positive correlation between E2 and FSH (r = 0.67, p < 0.0001) in the group of 106 patients, which remained significant in the group of hyperestrogenic men (n = 27, r = 0.68, p < 0.0001), but not in men with normal serum estrogen levels (n = 79, r = 0.10, NS). Other alterations: obesity in 18%, overweight in 30.2%, diabetes mellitus 4.7%, glucose intolerance 15%, hypertension 26% (14/53), hypergonadotropic hypogonadism 3.8% (one of them with an Emty Sella syndrome). Unexpectedly only nine patients (8.4%) out of the 106 consecutive patients recluted did not have any of the metabolic or endodrine abnormalities here described. These are more significant since 83% of the patients are younger than 40 years. The most interesting non previously described finding was the positive correlation observed between E2 and FSH when estradiol levels exceeds 50 pg/mL.