BACKGROUND: Increasingly there is an impetus on the part of surgeons to find more minimally invasive approaches to treat spinal pathologies. Retroperitoneal prepsoas and transpsoas approaches to the lumbar spine are one such example gaining increased attention. Endoscope-assisted approaches may help further reduce soft tissue dissection. OBJECTIVE: To describe an endoscope-assisted lateral retroperitoneal prepsoas approach for lumbar diskectomy. METHODS: Two fresh-frozen thoracolumbar cadaveric specimens were obtained and placed in the right lateral decubitus position. Using a left-sided, retroperitoneal prepsoas approach to the lumbar spine and under endoscopic visualization, diskectomies were performed at the L2/3, L3/4, L4/5, and L5/S1 intervertebral spaces. Qualitative assessment of the extent of central and contralateral foraminal decompression was performed. RESULTS: The endoscope was found to provide effective visualization at all disk spaces and combined with the anterior retroperitoneal prepsoas approach allowed for effective decompression of all explored disk spaces. Both operators noted difficulty obtaining visualization of the ipsilateral foramen, but adequate central and contralateral foraminal decompression was achievable for central, paracentral, and contralateral far lateral disk protrusions. CONCLUSION: Endoscope assistance may improve visualization of the lumbar intervertebral disk spaces during retroperitoneal prepsoas approaches and thereby help to expand the surgical indication for anterior and oblique lumbar interbody fusion.