In order to define the effects of chronic renal failure (CRF) in the progress of gingival inflammation, we studied 6 patients (4 male, 2 female) with CRF who were on chronic hemodialysis for 4.25 (range 1-15) years. Six healthy individuals, age and sex matched were used as controls. The protocol which we used comprised of two periods (a) a 40-day duration period of preparation and (b) a 28-day duration experimental period. During the (a) period, all subjects went through: (1) therapy of the chronic gingivitis and (2) complete control of dental plaque by oral hygiene. During the experimental period, all subjects were advised to avoid, for at least 21 days, any mechanical or chemical media of oral hygiene and went through photographing, recording of gingival index (GI), recording of plaque index (PII), and the collection and quantification of gingival crevicular fluid (GCF). On the 21st day, root planning and polishing were performed and subjects were advised to carry out oral hygiene. On the 28th day, all previous examinations (GI, PII, GCF) were repeated. In both patients and controls, GI, PII and GCF were increased on 7th, 14th and 21st day, without significant differences between the groups and returned to normal (close to zero point) on the 28th day. There are no significant differences between patients with CRF and normal controls in the evolution of experimental gingivitis. Therefore, chronic uremia has no effect on the defense of periodontal tissue against microbial plaque.