A man with three fully developed and well functioning kidneys was studied u
sing correlative imaging. Renal scintigraphy and the renogram not only play
ed a role in identifying the existence of three kidneys but also determined
the level of function of each kidney. The use of renal scintigraphy and re
nography is pivotal in the diagnosis of supernumerary kidneys. An abbreviat
ed review of embryogenesis is also given.