Transforaminal lumbar interbody fusion (TLIF) procedure is widely used, but the surgical indications for TLIF in elderly patients remain controversial because of potential risks such as inferior bone quality and higher rate of postoperative complications. Clinical efficacy and operative risk of TLIF in elderly patients are unclear. This study investigated the clinical effect and safety of TLIF for lumbar degenerative spondylolisthesis with radiculopathy or neurogenic claudication in patients aged 70 years or older. The clinical records were retrospectively reviewed of 35 consecutive patients aged 70-86 years (mean 74.8 years) who underwent one or two-level TLIF. The preoperative diagnosis included degenerative spondylolisthesis with segmental instability. Clinical outcomes were assessed by the Japanese Orthopaedic Association score, visual analogue scale, Oswestry Disability Index. Radiological fusion rate was also investigated. Clinical and radiological results were compared with those of 43 younger patients. Clinical outcome measures were significantly improved after operation in the elderly patients, but improvement rates were significantly lower than those of younger patients. Fusion rate was similar in both groups. Overall postoperative complications were increased in aged patients, although the prevalence of complications directly related to surgical technique was not significantly increased. Postoperative complications not related to the surgical procedure were factors affecting poor results. TLIF is acceptable for achieving clinical recovery and lumbar fusion with high radiographic fusion success even in elderly patients, although clinical benefits were limited compared with those of younger patients. Postoperative morbidity was mainly related to general or non-operative site complications.