Objectives: The aim of this study was to evaluate the success rate of transforaminal lumbar interbody fusion (TLIF) with unilateral pedicle screw fixation and contralateral posteromedial fusion by comparing clinical status before and after the surgical procedure. Success rate was defined by a reduction in pain intensity in the lumbar region and legs using the VAS scale before and after the procedure. Fusion was visible in standard X-ray of lumbar spine. Study outline: The study was set up as+ a retrospective-prospective study. It included 32 patients, 20 of whom were women, and 12 men. Participants and methods: Data from medical history obtained from medical records of the Department of Orthopedic Surgery, University Hospital Center Osijek, was used for research purposes. The collected data was used to evaluate the success of surgical method of TLIF with unilateral pedicle screw fixation and contralateral posteromedial fusion. The analyzed data included gender, age, etiology of the disease, spine level for fixation, pain evaluation in the lumbar region and legs using VAS scale before and after the surgery, fusion and paresis of the peroneal nerve. Results: The median age of patients at the time of surgery was 58. The most common etiology of the disease is discogenic pain in 17/32 participants. The most common spine level for fixation is L4 – L5 in 16/32 participants. Fusion was accomplished in 27/32 participants. 3/32 participants had experienced paresis of the peroneal nerve. The difference in pain intensity in the lumbar region and legs before and after the procedure was statistically significant and it confirms the efficiency of the procedure. Conclusion: Significant reduction of pain was achieved in the treatment of discogenic pain with TLIF with unilateral pedicle screw fixation and contralateral posteromedial fusion.