How long after a dog dies does it start to smell?

After a dog dies, its body generally starts to smell in about 2-3 days, and the process speeds up in high temperatures. The smelling is the process of bacterial decomposition, during which the body produces large amounts of ammonia gas with a very foul odor.

Note that some substances from decomposed low-grade proteins are highly toxic, so the body should be handled properly and promptly. If the dog died from an infectious or otherwise contagious disease, do harmless disposal quickly after death to prevent spread.