The aim of this study was to determine the mean serum and follicular fluid LH and estradiol values in patients treated by IVF/ET (ICSI) after completed ovarian stimulation and to determine the range of values for these hormones with higher chances of conceiving pregnancies. All patients underwent stimulation in long agonistic protocol. Collected samples of body fluids (serum n = 31, follicular fluid n = 93) were centrifuged and supernatant was separated, aliquoted, frozen and stored at − 20°C. LH and E2 were measured in serum and follicular fluids. Cutoff value of E2 determined using follicular LH and follicular E2 correlation was 2100 nmol/L. If the E2 value was lower than 2100 nmol/L the ratio of results related to pregnancy was 29,4% (15/51). If the follicular E2 values were higher than 2100 nmol/L the ratio of results related to pregnancy was (7,1%, 3/42). The observed differences were significant (p 0.03). Follicular LH values higher than 3.1 IU/L and follicular E2 values < than 2100 nmol/L indicate higher conceiving probability. Our results can be fit in previous findings on negative effects of low LH values in IVF treatment procedures.