Venous intravasation during myelography is of rare occurrence. A single instance was observed in 575 myelographic studies made in this hospital. A white married female, aged 44, was admitted to the hospital with a history of low back pain for four years and right leg pain for two months. Four years before admission, while lifting a basket of clothes, she became conscious of something “giving way” in her back and of a dull aching pain on the right side. She went to an osteopath, who “manipulated” her back, and she was relieved. This she did several times. Two months before she was seen at the hospital, she had a cold, during which she coughed and sneezed repeatedly. At that time she suddenly had a severe pain in the back radiating down the right leg to the toes. This remained constant, and at the time of entry the patient had noticed a weakness of the right leg and numbness of the lateral part of the right foot. The findings on physical examination were not significant. Neurological examination showed the cranial nerves to be intact. Hypesthesia was present on the lateral aspect of the right leg and foot. The Achilles reflex on the right was absent. The back flexed 30 degrees, with buttock pain on the right. Extension and lateral bending were normal. Urinalysis was negative. The red blood cell count was 3,880,000; hemoglobin 12.1 gm., 71 per cent; white cell count 8,000, with polymorphonuc1ears 61 per cent and lymphocytes 39 per cent; Wassermann and Kahn tests negative. The cerebrospinal fluid showed 5 white blood cells and 3,500 red cells; the Wassermann reaction was negative; the colloidal gold curve 0000000000. Lumbar myelography was done. The opaque oil was injected in the fifth interspace and revealed a large filling defect on the right of L-5. The pantopaque was seen to leave the spinal canal through the venous plexus in the area, and within three minutes the greater part was gone. Fluoroscopy of the chest at the time revealed no evidence of opaque oil there, and later films of the abdomen showed no evidence of oil in the pelvis or abdomen. The patient was operated on, and a moderate amount of adjacent lamina on the right side was rongeured away. Immediately underlying the first sacral root was a large mass consisting of nuclear material which had extruded completely through a hole in the annulus fibrosus. An incision was made into this mass of herniated material, following which it was removed in its entirety with the grasping forceps. The hole in the annulus was then enlarged, the disk space was curetted, and all available nuclear material was removed. The ligamenta flava were then removed between L-4 and L-5 on the right side, and exploration was undertaken. Normal anatomical relations existed here. Articular facets between the 4th and 5th lumbar segments were cleared of their cartilage by means of a curved osteotome and curette, and the bony surfaces were freshened.