Objective: To assess the association between secondary trauma from occlusion and the severity of periodontitis. Method and Materials: A total of 288 subjects with chronic periodontitis of varying severity and 93 healthy subjects were included in the study. Premature and balance contacts were identified by manual palpation and visualization of occlusal contacts during clenching in habitual intercuspation and lateral or protrusive movements of the mandible. Statistical analysis was performed with Kruskal-Wallis, Mann-Whitney, and Spearman correlation tests. Results: Statistically significant differences (P .001) were found for all variables tested (ie, the total amount of trauma per patient and the number of premature and balance contacts increased significantly with the level of clinical attachment loss). The Spearman test showed a statistically significant correlation between the total amount of trauma per patient and the severity of periodontitis (P .001). Conclusion: The results of this study indicate that secondary trauma from occlusion (ie, premature and balance contacts) is frequently seen in periodontally compromised patients and is positively correlated with the severity of attachment loss. Keywords: occlusion, periodontitis, prevalence, trauma from occlusion