Objective: To assess whether pregnancy rate differs in unilateral vs bilateral transfer in “immediate transfer of injected oocytes into the fallopian tubes.”Design: Prospective randomized clinical trial. Setting: Tertiary university hospital. Patient(s): The study population included 160 patients presenting with male factor infertility who fulfilled the criteria for immediate transfer of injected oocytes into tubes. Intervention(s): Four injected oocytes were transferred into two tubes (study group) or one tube (control group). Main Outcome Measure(s): Implantation rate, clinical pregnancy rate, multiple pregnancy rate, and incidence of pregnancy with unknown location (PUL). Result(s): A total of 72 (45%) pregnancies were achieved. There were 32 pregnancies (1 PUL, 4 multiple, and 27 singletons) in the bilateral transfer group and 40 pregnancies in the unilateral transfer group (1 PUL, 7 multiple, and 32 singletons). No significant difference was found in the implantation rate, clinical pregnancy rate, multiple pregnancy rate, and incidence of PUL. Conclusion( s): This study demonstrates that no difference in outcome occurred between unilateral and bilateral transfer in microinjected oocytes intrafallopian transfer (MIFT). Therefore, along with the same outcome parameters, unilateral transfer is the preferred method of MIFT. Objective: To assess whether pregnancy rate differs in unilateral vs bilateral transfer in “immediate transfer of injected oocytes into the fallopian tubes.” Design: Prospective randomized clinical trial. Setting: Tertiary university hospital. Patient (s): The study population included 160 patients presenting with male factor infertility who fulfilled the criteria for immediate transfer of injected oocytes into tubes. Intervention (s): Four injected oocytes were transferred into two tubes (study group) or one tube (control group). Main Outcome Measure (s): Implantation rate, clinical pregnancy rate, multiple pregnancy rate, and incidence of pregnancy with unknown location (PUL). Result (s): A total of 72 (45%) pregnancies were achieved. and 27 singletons) in the bilateral transfer group and 40 pregnancies in the unilateral transfer group (1 PUL, 7 multiple, and 32 singletons). No significant difference was found in the implantation rate, cli Conclusion (s): This study demonstrates that no difference in the progression of between unilateral and bilateral transfer in microinjected oocytes intrafallopian transfer (MIFT). Thus, along with the same outcome parameters, unilateral transfer is the preferred method of MIFT.