The range of winners included firms that created makeshift toilets after Japan's 2011 quake-tsunami disaster, Haneda airport for its spotless restrooms, and the organisers of a toilet-themed art festival.
Others got the nod for making female restrooms more attractive, including supplying space for breast-feeding and shortening waiting lines.
Toilets in Japan have been raised to something of an art and foreign visitors are regularly wowed by their seat warmers and pinpoint bidet jets.
But the government insists the award was more than just a beauty contest -- it was about empowering women.