Introduction: MRI-Ultrasound (MRI/US) fusion-guided transperineal prostate biopsy (TPB) is gaining popularity in the diagnostic algorithm of prostate cancer. It is associated with higher pain score than the other methods of prostate biopsy. Effective analgesia is a key point for providing patient comfort and preventing his movement in response to pain with subsequent mismatch of the fused MRI/ US images. The mismatch could lead to inaccurate targeting of suspected cancer lesions. The preferred method of analgesia in an outpatient setting is topical intrarectal administration of lidocaine and periprostatic nerve block, but the pain and the discomfort from the procedure are not completely eliminated. Hypothetically, saddle block anesthesia has an expected better efficacy in relieving the pain from the MRI/US-TPB. Aim: To evaluate the efficacy and safety of saddle block anesthesia in patients undergoing MRI/US-TPB and сomparative analysis between patients who have received and have not received intravenous fentanyl Material and methods: A prospective randomized study was conducted on 12 consecutive patients undergoing MRI/US-TPB. Saddle block anesthesia was performed with 20 mg prilocaine hydrochloride 2% hyperbaric solution to all patients. 6 patients received intravenous fentanyl at a dose of 1mcg/kg (Group 1) and 6 patients did not receive intravenous fentanyl. It was examined: patient’s age, weight, height, BMI and ASA class; duration from the dural puncture to the end of the surgical intervention; taken number of prostate biopsies; presence of intraoperative pain; motor blockage; presence of a difference of more than 20%, before and after saddle block anesthesia, of non-invasively measured blood pressure and heart rate; additional medication; presence of early postoperative complications and recovery time from anesthesia Results: The comparative analysis of the preoperative characteristics of the both groups did not reveal significant statistical difference. There were comparatively similar indicators for surgical intervention and regional anesthesia in both groups. The both anesthesia techniques showed safety profile with hemodynamic stability, without additional medicine administration and lack of early post-anesthesia complications. Pain did not occur during inserting and moving the US probe into the anal canal and puncturing the perineal skin and the underlying tissues. 50% (3) of the patients in Group 2 had pain during the puncture of the prostate gland and biopsy extraction, while in Group 1 - 0% (0) of the patients reported presence of pain. There was a slightly delayed onset of the first postoperative pain in Group 1 - 113.17 ± 15.11 min. compared to Group 2 - 99.83 ± 11.51 min. Conclusion: The saddle block anesthesia with 20 mg prilocaine hydrochloride 2% hyperbaric solution in combination with intravenous fentanyl at a dose of 1 mcg/kg is a safe anesthesia technique, associated with excellent analgesic profile, low incidence of anesthesia-related complications and rapid recovery in patients undergoing MRI/US-TPB. Key words: saddle block, transperineal MRI/US fusion-guided prostate biopsy, prilocaine hydrochloride 2% hyperbaric solution