Formation of plaque on the surfaces of dentures is a common problem among denture wearers. A study was conducted to determine the distribution of plaque on dentures. The plaque material was disclosed with a dye solution and measured with a modified Quigley-Hein scale. A photographic method was used to determine the distribution of plaque on the dentures of a group of complete-denture wearers. The effectiveness of a perborate soak-type cleanser was also measured by studying the precleaned and postcleaned states of the denture. Denture plaque was more evident on the fitting surfaces of the dentures than on areas of the flange, teeth, and palate. The use of the soak-type cleanser alone may not be completely effective for the control of heavy plaque.