Posterior lumbar interbody fusion (PLIF) with cages can be combined with decompression of the spinal canal and with instrumented posterolateral fusion (IPLF) with pedicle screws, through a single posterior incision. The authors wanted to assess retrospectively the clinical and radiological outcome of PLIF + IPLF performed by the senior author. Between July 1997 and December 2003, 75 patients underwent PLIF with cages and IPLF with transpedicular instrumentation, for either degenerative disc disease, stenosis, spondylolisthesis or post-discectomy syndrome. The clinical outcome was evaluated according to the criteria of Kirkaldy-Willis. Flexion/extension radiographs and CT-scans were obtained in cases where there was any doubt about the fixation/fusion status. The mean age was 48.7 years (range: 30 to 75). The mean duration of follow-up was 29.17 months (range: 12 to 67). The clinical outcome was excellent or good in 85.3% of the patients. There were 4/75 patients (5.3%) who failed to return to their original occupation. Four posterolateral fusions were uncertain, but all anterior fusions succeeded: thus circumferential fusion was obtained in 71 out of 75 cases, or 94.6%. Three patients sustained a neurological complication, but only one was left with a partial drop foot. The results were comparable with similar studies. Therefore the authors recommend further use of PLIF + IPLF in painful lumbar degenerative spinal disease where conservative management has failed.