STUDY DESIGN Basic fibroblast growth factor immunoreactivity was studied in disc herniation tissue. OBJECTIVES The first objective was to analyze in which tissue components, if any, fibroblast growth factor is expressed in the disc herniation. The second objective was to compare such expression with that in fresh cadaver disc tissue. SUMMARY OF BACKGROUND DATA Disc herniation tissue contains vascular ingrowth, which promotes the formation of granulation tissue. Fibroblast growth factor is a potent inducer of angiogenesis and also regulates extracellular proteolysis. METHODS Twenty-seven disc herniation tissue and five macroscopically normal fresh cadaver discs were treated with an identical immunohistochemical protocol. Serial frozen sections were stained with a polyclonal basic fibroblast growth factor antibody and a polyclonal antibody to von Willebrand factor, which localizes endothelial cells. The immunostaining data were compared with relevant clinical data. RESULTS Histologically, 74% of the samples contained anulus fibrosus and 59% nucleus pulposus. Basic fibroblast growth factor immunoreactivity was detected in 81% of the samples. There were immunopositive small blood vessels and scattered immunopositive disc cells (67%). Not all observed blood vessels were basic fibroblast growth factor immunopositive. In control discs, no immunoreactivity was observed. CONCLUSIONS The observed presence of fibroblast growth factor in small blood vessels suggests an active angiogenesis as a result of disc injury. Cellular expression of fibroblast growth factor may be linked to proteolytic activity in disc extracellular matrix.