This study focuses on preparation and evaluation of ¹³¹I-bevacizumab by Iodogen method for targeting VEGF over-expressing cancers for therapy. 131I-Bevacizumab exhibited radiochemical purity of 98.0±0.7%. In vitro stability of ¹³¹I-Bevacizumab was retained at >85% in both saline and serum at 37°C upto 5 days post iodination. In vitro cell studies showed good immunoreactivity and uptake by VEGF expressing tumor cells. Uptake and retention of 131I-Bevacizumab in tumor with reduction in uptake in presence of cold Bevacizumab confirmed its specificity to VEGF.