Generalized aggressive periodontitis (GAP) is a subgroup of periodontal diseases among 20-35 years age group adults. Several studies have reported the association of interleukin-1β gene polymorphism with periodontal diseases among different populations. The present study aimed at investigating the presence of IL-1β polymorphism in GAP patients in Iran. Further, the presence of IL-1β(+3954) gene polymorphism was evaluated in the GAP patients (n=26) and healthy individuals (n=26). All three genotypes (A1A1 [56%], A1A2 [28%], and A2A2 [16%]) were observed in healthy individuals, whereas only A1A1 (38.5%) and A2A2 (61.5%) were the genotypes observed in the patients. There was a significant positive association between distribution of IL-1β genotypes and the risk of periodontitis disease (p=0.017). Further, there was a significant positive association between probing pocket depth and IL-1β genotypes of patients (p=0.014). However, no meaningful correlation between genotype-clinical attachment loss and genotype bleeding on probing with the risk of GAP (p=0.418, p=0.819, respectively) was found. In conclusion, findings of the present study demonstrate a positive association between IL-1β gene polymorphism and risk of periodontitis disease.