Background. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a widely accepted surgical procedure. But there are only a few reports of MIS-TLIF using the unilateral approach and single cage in elderly patients. Objective. The study investigated the clinical and radiological outcomes of MIS-TLIF using the unilateral approach and single cage in the patients over 65 years of age. Methods. Thirty-eight patients were followed for a mean of 15.5 ± 11.61 months. Radiological data include fusion rate, change of disc height, and central canal area. The numeric rating scale (NRS) and Oswestry disability index (ODI) were used to assess clinical outcomes. Results. The mean age of these patients at operation was 71.82 ± 4.71 years (range, 65-82 years). Evidence of fusion was observed radiologically in 64.71% at 6 months and 87.5% at 12 months after surgery, giving a final fusion rate of 100%. The mean NRS scores for back and leg pain and ODI scores improved significantly at the final follow-up. Conclusions. Clinical and radiologic outcomes of MIS-TLIF using unilateral approach and single cage in elderly patients indicate an acceptable method for the treatment of various kinds of lumbar spinal diseases.