Usually, coccydynia cases are caused by herniated discs, with lower back pain and sciatica as initial symptoms. However, whether lumbar disc herniation causes coccydynia without back pain remains unclear. We report a case of lumbar disc herniation diagnosed as the underlying cause of coccydynia by discoblock. A woman in her mid-20s was treated for coccydynia experienced during sitting, for several years. There was no coccyx tenderness upon palpation. As the location of the pain could not be identified, it was not possible to perform a block at the site of the pain. Magnetic resonance imaging showed a herniated L5/S1 lumbar disc, without lower back pain and sciatica. Following discoblock, coccydynia was diagnosed as associated pain due to the herniated L5/S1 lumbar disc that was treated with percutaneous discectomy. After surgery, coccydynia was relieved while sitting; no medication was required.Discoblock was used to diagnose lumbar disc herniation as the cause of coccydynia. Percutaneous discectomy was effective for coccydynia without back pain, thus lumbar disc herniation should be considered as a differential diagnosis. Discoblock can be useful for differentiation.