One of the best ways to become more proficient at grant writing is to review funded applications. While the following sample applications are from the National Institute of Allergy and Infectious Diseases (NIAID) and the National Cancer Institute (NCI), they are applicable to all NIH components.
NIAID has released sample applications for research grants (R01, R03, R21, R21/R33) and K Awards (K01, K08). Check out the sample applications complete with associated summary statements.
Looking for more samples of NIH applications?
Check out the offerings available from NCI's Division of Cancer Control and Population Science:
Behavioral Research Grant Sample Applications
Cancer Epidemiology Research Grant Sample Applications
Dissemination and Implementation Research Grant Sample Applications