Tumor growth and metastasis depends on angiogenesis. Vascular endothelial growth factor (VEGF) is a potent mitogen for vascular endothelial cells in vitro and promotes neoangiogenesis in vivo. Objective: Follicular thyroid cancers(FTC) are a vascular tumor and traditionally metastasize via blood vessels. Likely other cancers, angiogenesis may playa important role in FTC. We, therefore, investigated the expression of VEGF and microvascular density by immunohistochemistry in FTC and follicular adenoma(FA). Materials and Methods: Findings of immunohistochemical stainings for VEGF and CD31 were measured by grading scale from +1 to 4+(strongest) and by counting the stained microvessels in 14 FTCs and 14 FAs. Results: 1) Expression of VEGF. a) FTCs have stronger expression than FAs in areas of tumor adjacent to capsule($mean{pm}SD:;3.2{pm}0.9;vs;2.0{pm}0.9$, p<0.01) and in central area($2.3{pm}0.7;vs;1.3{pm}0.6$, p<0.01). b) The VEGF expression of capsular area in FTCs are higher than that of central area(p<0.05). 2) Microvascular density by CD31. a) FTCs have more microvessels than FAs in areas of adjacent to capsule($78.9{pm}27.3;vs;38.7{pm}15.6$, p<0.01) and in central area($75.5{pm}23.3;vs;27.8{pm}10.7$, p<0.01). b) In FTCs, the number of microvessels of capsular area are more than that of central tumor area, but not significant statistically(p>0.05). Conclusion: The higher expression of VEGF and microvascular density in FTC suggests angiogenesis plays an important role in progression of FTC.