Of examined 37 breast cancer patients (average age 42,3 +/- 1,2 years) 25 had not had any specific therapy by the date of investigation and the rest 12 had received in average 5,3 +/- 0,6 cycles of neoadjuvant chemotherapy mainly TAC and FAC. It was revealed that such kind of treatment conformed to valid decrease of both testosterone level and ratio value [(testosterone concentration/follicle stimulating hormone concentration, FSH) x 100] in blood serum. Testosterone level in blood of patients in fact decreased to similar values both in amenorrhea induced by adjuvant chemotherapy and saving menorrhea. This is a confirmation that maintenance of menorrhea does not mean intactness of ovarian function (ovarian reserve) and indicates that evaluation of testosteronemia in these circumstance at least does not give in estimation of estradiol and FSH's content in blood. Further attention could be paid to study testosteronemia before and after neoadjuvant chemotherapy as a potential additional prognostic factor of efficacy of this treatment for breast cancer patients.