The overall success rate of getting an NIH grant funded in 2009 was 20.6 percent, reports Writedit at Medical Writing, Editing & Grantsmanship. She breaks the data down further to find that R21s have success rates below those of R01s and lists grant success rates for R21s at some of the major institutes: 14.5 percent at NHLBI, 13.7 percent at NCI, and 7.9 percent at NIGMS. NIMH has a high R21 success rate, coming in at 20.1 percent.