The purpose of this study was to assess the obesity in correlation with the demographic characteristics, nutritional habits and knowledge among adult obese patients. We used a data collection method carried out with 500 obese adult volunteer patients Afyonkarahisar State Hospital between March and August 2011. Nutritional habits and knowledge score was measured by analysis of 22 question responses and demographic characteristics were sought by questionnaires. Most of obese patients were married (94%), female (85.4%), housewives (75.6%) and settled in province (73.2%). Moreover almost all stated to have breakfast everyday (91.4%) and to prefer vegetables (48.8%) for main meals. Increased emotional eating (71%), from birth and childhood start of weight gain (66.8%), familial story of overweight (79.6%) and no balanced (86.6%) and regular (92.8%) diet consumption were observed among obese patients. Their general knowledge in terms of nutrition was not impressive. Also, they were mostly observed to be interested in health and nutrition related issues (68.4%), nor take physical exercise (87.8%), and were accustomed to eating rapidly (55.2%). Our data also confirmed that lower education level was significantly associated with obesity. Obesity is observed to be significantly associated with some the nutritional habits, nutrition knowledge and demographic characteristics of the patients. The diet quality and physical activity must be promoted with health education programs for all segments of the population with a special focus on woman. Understanding of the complex interplay of several factors may help to increase public awareness and to establish obesity prevention strategies.