In 70 healthy obese subjects (37 men and 33 premenopausal women; aged 27-51 yr; body mass index, 28-38 kg/m2), associations between the initial amount of visceral fat and sex hormone levels were studied as well as between changes that occurred in response to a 4.2 mJ/day deficit diet for 13 weeks. Magnetic resonance imaging was used to quantify the visceral fat depot. In women, an abundance of visceral fat was significantly associated with diminished levels of sex hormone-binding globulin and free 17 beta-estradiol/free testosterone (T) ratio and to elevated levels of free T after adjustment for age and total fat mass. In men, no significant relationships could be found between visceral fat accumulation and any of the sex hormones. Mean total fat loss was 11.3 +/- 3.3 (+/- SD) kg. In women, loss of visceral fat was significantly related to rises in the sex hormone-binding globulin level and the free 17 beta-estradiol/free T ratio independent of total fat loss, whereas in men, only the association between visceral fat loss and increased estrone level reached statistical significance. In conclusion, in obese premenopausal women, visceral fat predominance seems to be related to a relatively increased androgenicity. In obese men, sex steroid levels appear not to depend on the amount of visceral fat. In obese women, but not in obese men, visceral fat loss seems to be accompanied by a relative reduction in androgenicity.