Vascular endothelial growth factor (VEGF) is considered a potent stimulator of angiogenesis. In multiple myeloma (MM), it has been reported that bone marrow angiogenesis parallels tumor progression and correlates with a poor prognosis. To investigate the role of angiogenesis in MM, we investigated VEGF expression and microvessel density (MVD) in the bone marrow of 75 MM patients by immunohistochemical methods. VEGF expression was observed in 87.3% (62 of 71) of patients. MVD was 69.42 +/- 9.67 (mean +/- SE) compared with the normal control values of 26.81 +/- 2.85. MVD values were 73.98 +/- 11.27 and 36.04 +/- 6.99 in the VEGF-positive and VEGF-negative groups, respectively. The MVD of patients in the VEGF-positive group was significantly higher than in the VEGF-negative group (P = .045). However, there were no significant differences in various clinical parameters, such as age, sex, hemoglobin, platelet count, serum levels of albumin, calcium, creatinine, and beta2-microglobulin, and bone marrow plasma cell percentage, between the VEGF-positive and VEGF-negative groups. Multivariate analysis revealed that age, hemoglobin, platelet count, serum levels of albumin and creatinine, and bone marrow plasma cell percentage were correlated with overall survival, whereas VEGF expression or MVD was not. In conclusion, our results suggest that VEGF is highly expressed and that MVD is increased in MM, indicating that angiogenesis may play a role in MM. Although MVD in the bone marrow of the VEGF-positive group is significantly higher compared with the VEGF-negative group (P = .045), VEGF is not correlated with overall survival. Further studies that include other angiogenic factors are needed to determine the functional role of angiogenesis in MM.