Periodontitis is considered to be a multifactorial disease. Studies have indicated that part of the clinical variability in periodontitis may be explained by genetic factors. Genes can affect the immunoinflammatory host response to bacterial challenge in the periodontal tissues by means of an overproduction of proinflammatory cytokines, such as interleukin-1 (IL-1). IL-1 plays an important role in the pathogenesis of periodontitis, through its involvement in the regulation of the host's inflammatory response and bone resorption. Therefore, the genes that encode for IL-1 production have recently received most attention as potential predictors of periodontal disease progression. Hence, the relationship between IL-1 genotype and periodontal disease has been investigated by a number of studies. This review article aimed to determine whether IL-1 could be regarded as a genetic marker for periodontitis by reviewing data concerning susceptibility, clinical parameters, and treatment strategies in relation to the IL-1 genotype. The review concluded that there is currently limited evidence to implicate a specific IL-1 genotype as a risk factor for chronic periodontitis in white populations. However, there is limited evidence that genetic variation in the IL-1B polymorphism could be a risk factor for aggressive periodontitis.