62 patients scheduled for one- or two-level posterolateral lumbar fusion were randomized to a local bone autograft with or without the addition of platelet-rich plasma. Patients were assessed for bone fusion on CT, as well as clinical outcome on visual analog scales for back pain, leg pain, and leg numbness. Follow-up was scheduled for the first 2 years after surgery. For bone fusion, union rate and time to union significantly favoured the PRP group compared to the control group. Nonetheless, no significant differences between groups were observed in VAS back pain, VAS leg pain, or VAS leg numbness scores at any time point.