A 56-year-old obese man with a body mass index of 30.9 kg/m² presented with left sciatica and intermittent claudication. Computed tomography scans showed a posterior vertebral scalloping change in L3, L4, and L5. Meanwhile, magnetic resonance imaging revealed epidural mass posterior to the L3, L4, and L5 vertebral bodies. The solitary mass was isosignal to subcutaneous fat and asymmetrically compressed to the left side of the dural sac and L4 nerve root, as observed on axial T1- and T2-weighted images. To the best of our knowledge, there have been few reports of a solitary epidural lipoma causing lumbar radiculopathy. The patient underwent transforaminal lumbar interbody fusion at L4-L5, and his symptoms then resolved. Thus, we recommend decompression and fixation as appropriate management for lumbar radiculopathy caused by epidural lipoma located on the ventral side of the dura and intervertebral foramen.