The management of degenerative spondylolisthesis with laminectomy alone or laminectomy with fusion remains controversial. From the early 1970s to 1996, 290 patients with degenerative spondylolisthesis were treated with 249 laminectomies and 41 fenestration procedures over an average of 3.2 levels. One level olisthesis was encountered in 250 patients, and two levels of slip in 40. Patients averaged 67 years of age, and were followed an average of 10 years. Using Prolo's outcome scale, 69% of patients exhibited excellent, 13% good, 12% fair, and 6% poor outcomes. Secondary decompressions with fusions for increased olisthy/instability (five patients) and recurrent stenosis/disc disease/instability (three patients) required one posterolateral "in situ" fusion and seven Texas Scottish Rite Hospital instrumented procedures. Decompression alone successfully managed degenerative spondylolisthesis in 290 patients treated over 3 decades, because only 8 (2.7%) required secondary fusion.