Obesity is a common comorbidity of type-2 diabetes and one of the most modifiable risk factors for preventing other comorbid conditions, such as diabeticnephropathy and cardiovascular disease. Using a cross-sectional design, this study aimed to determine eating behavior, factors related with obesity and thedominant factor of obesity in patients with type-2 diabetes. Data were collected from 133 members of the Chronic Disease Countermeasure Program inJatinegara Primary Health Care, East Jakarta, that were selected using purposive sampling. Food intake was assessed by 1 × 24-hour food recall and theFood Frequency Questionnaire, Physical activity was assessed by the Global Physical Activity Questionnaire. Results showed that 63.9% of the surveyedtype-2 diabetics were obese (body mass index ≥ 25 kg/m2) and that the respondents consumed more fat than the recommended value (30.77% ± 9.06%)but less energy than the required value (62.06% ± 23.67%). The prevalence of obesity among adults with type-2 diabetes could be associated with nutritional knowledge, education level, and the length of suffering from the disease. Nutritional knowledge was found to be a dominant factor associated with obesity.