Ultrasonic bone-cutting instruments have gained traction in open and minimally invasive spine surgery because of their selective bone-cutting capability while preserving adjacent soft-tissue structures. However, their use in uniportal endoscopic spine surgery has not been reported in the peer-reviewed literature. This technical note describes a uniportal endoscopic surgical technique that uses an ultrasonic osteotome for uniportal endoscopic lumbar interbody fusion (U-ELIF) and reports preliminary outcomes. Specifically, we describe the technical nuances of ultrasonic osteotome use in U-ELIF and evaluate its feasibility and safety, with an emphasis on minimizing complications.