BACKGROUND : Diabetes mellitus is a common chronic disease with increasing prevalence world wide; it leads to devastating human, social and economic impact. OBJECTIVE : this study were to determine the level of diabetes-related knowledge, attitude, and practice among adult diabetic patients in central region and finding correlation between knowledge, attitude and practice regarding diabetes. METHODS : A descriptive study was conducted on 300 diabetic patients on internet using Monkey Survey from 7th to 24th April 2015. A questionnaire was filled out. SPSS version 22 was used for data analysis. Descriptive statistics were comprising percentages, and frequency in order to describe knowledge, attitude, and practice. Correlations between main outcomes variables were calculated by means of Pearson product-moment correlation coefficient (r) that measures the linear relationship between two variables. P-value ≤0.05 were regarded as statistically significant. RESULTS : In the studied sample, 47% were age more than 45 years. About 71.4% of cases were females. The level of knowledge and attitude had 'good' in 73.6%, and 87.7% respectively but level of practice had poor in 45% of patients. There were good correlations between knowledge, attitude and practice. Significant positive linear correlation between knowledge and attitude (r = 0.503, P < 0.001), knowledge and practice (r = 0.337, P < 0.001), and statistically significant linear correlation between attitude and practice (r = 0.235, P < 0.001). CONCLUSIONS : The overall knowledge and attitude were good, while diabetes-related practice were poor. However results indicate that an increase in knowledge will increase attitude, and practice. A better educational program on diabetes should be conducted to improve patients' attitude, and practice towards diabetes.