Objective: describing the factors associated with knowledge, attitudes, and practices on the using insulin of the elderly diabetic patients. Subjects and methods: cross-sectional description of the patients diagnosed with diabetes according to WHO's criteria 2006. Results: The average age was 76.82 + or - 7.9, female/male = 1.7. The number of patients with duration of diabetes or = 10 years accounted for 51 percent. The right knowledge of using insulin was higher in the patients with higher education (17 percent) and co-morbidity (32 percent), positive attitudes on using insulin in the group of average-high economic conditions (75 percent) and duration of diabetes more than 10 years (41 percent), proportion of co-morbidity patients with right practice was 73 percent. Condusion: right knowledge related to education and co-morbidity, positive attitudes associated with economic conditions and duration of diabetes, true practice of using insulin associated with co-morbidity.