Several studies have proved transrectal ultrasonography (TRUS) is efficient in the evaluation of patients with hematospermia, but the numbers of patients were less than 60 in each of the previous reports. Herein, a total of 270 patients with hematospermia were evaluated by TRUS to assess its efficacy in the etiologic diagnosis of hematospermia. The age of patients ranged from 15 to 75 years (x, 41.2 years), and the duration of symptoms was 1 day to 8 years (x, 3.4 months). Abnormalities were revealed by TRUS in 256 patients (94.8%). The percentages of pathological conditions located in the seminal vesicles, in the ejaculatory ducts, in the prostate, and in the bladder were 46.3% (125 cases), 29.6% (80 cases), 55.2% (149 cases), and 0.4% (1 case), respectively. The number of patients older than 40 years old and 40 years old or younger were 126 and 144, respectively. Our results show significantly higher percentages for malignant diseases, prostatic calcification and benign prostatic hyperplasia in the group of patients more than 40 years old compared with the group of patients 40 years old or less. Eight of 270 patients (3.0%) had malignant tumors, and all of the 8 malignancies occurred in patients more than 40 years old. TRUS is a noninvasive, reliable tool for the investigation of causes of hematospermia. Hematospermia is generally a benign symptom in younger patients. Special attention should be paid to elderly patients to exclude malignancy.