The aim was to investigate the relation between optical density of seminal plasma, serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in azoospermic patients and to establish criteria depending on optical density measurements in order to estimate serum FSH and LH levels. Optical density of seminal plasma and serum FSH and LH levels were measured in 45 azoospermic patients. The semen samples with an optical density (OD) of more than 0.5 showed normal levels of FSH and LH, while those with less than 0.5 were observed to have high levels of FSH and LH. The optical density of seminal plasma can be used in the prediction of serum FSH and LH levels in azoospermic patients.