BACKGROUND: In the past, research has shown that a higher body mass index (BMI) is one of the variables that increase the likelihood of kidney stones; however, no studies have found a connection between the two in the type II diabetic population. The purpose of this research is to reveal the association between BMI and kidney stones in the type II diabetic population. METHODS: We selected demographic data, laboratory data, lifestyle, and medical history from the NHANES. Specifically includes age, gender, systemic immune-inflammation index (SII), poverty income rate (PIR), body mass index (BMI), kidney stones, education, coronary artery disease, smoking, and drinking. RESULTS: BMI and kidney stones were shown to have a positive association in type II diabetics (blood sugar level > 7.0 mmol/L or diagnosed by a doctor) (OR = 1.021, 95% CI 1.008-1.033, P = 0.001), even after controlling for factors, such as age, gender, race, education level, coronary heart disease, smoking, and drinking. The subgroup analysis revealed a more significant positive association among the 67-80 years, female and Non-Hispanic White population. CONCLUSIONS: There is a positive correlation between BMI and kidney stones among the type II diabetic population.