The objective of this study was to determine the severity of gingivitis of newly erupted permanent teeth of dogs which had exhibited plaque and gingivitis around the predecessor deciduous teeth. Two litters of 4 and 6 mongrel dogs were assessed clinically using G. I. and P1.I. (Löe 1967) and tests for crevicular exudate. Selected premolar gingiva were biopsied and processed for light microscopy. A plaque inducing diet was fed to 2 dogs in each litter. Control dogs were fed a hard diet and subjected to regular plaque removal procedures, using daily toothbrushing and 0.2% chlorhexidine application. Clinical examinations on canines and premolars were made at weekly intervals from the 16th to the 30th week of age.Results showed that in control dogs, teeth from which plaque was removed regularly exhibited non‐inflamed gingiva throughout the study. Gingivitis in experimental dogs was relaed to the continued presence of plaque. In these dogs, the mean G.I. and P1.I. scores of permanent teeth were significantly higher (p<0.001) than those of the predecessor deciduous teeth which had exhibited plaque and pingivit