i would not recommend shooting a deer in the kidney because there is such a small margin for error. if you miss the kidney as strut stated you're probably gonna trash the tender loins. however it is probably the most lethal shot you can make. a hunting buddy of mine made that comment to me a while back about it being very lethal. several yrs ago i had a small buck come in, i came to full draw and let out a soft grunt to stop him and he took 1 too many steps and stopped w/his head and shoulders behind a tree. if i let him pass the tree i wouldn't have a shot. back then i was shooting a WWWWHHHHOOOLLLEEEE bunch... 3D tourney's, practicing constently, and this deer was dead nuts 20 yds and had the confidence to make the shot....that and wanting to see if my buddy was wright about a kidney shot....so i placed and arrow dead center of the hollow spot just above and a little foreward of the rear leg and the deer dropped like a rock. i actually thought i might have spine shot him but after i retrieved him the hole was right where i aimed. while feild dressing him i checked and had dead centered the kidneys. had i not been practicing and had the confidence that i did back then i wouldn't have dreamed of taking that shot.