We examined the impact of the severity of periodontal disease on quality of life in adults with chronic periodontitis. One hundred patients (age, 30-58 years) who were assisted at the Basic Health Care Unit in the city of Passo Fundo, RS, Brazil underwent clinical examination of all standing teeth, including gingival bleeding on probing, probing depth, and clinical attachment level, and were divided into those with mild/moderate (n = 49; group G1) and severe (n = 51; group G2) chronic periodontitis. The participants were then interviewed, using a structured questionnaire. The Brazilian Oral Health Impact Profile (OHIP-14Br) questionnaire was used to assess oral health-related quality of life. Associations were investigated, and those with a P value of less than 0.2 were tested using multiple logistic regression models. Those with a P value of 0.05 or less were considered significant. There was a significant association between G2 and education level (P = 0.00051). OHIP-14Br score was higher for G2 (24.1) than for G1 (18.2) (P = 0.0455). Severe chronic periodontitis was associated with low education level (≤8 years) (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.2-7.3) and pronunciation difficulties (OR, 3.1; 95% CI, 1.0-9.3). In conclusion, periodontal disease severity was inversely associated with quality of life among Brazilian adults. (J Oral Sci 57, 87-94, 2015)