Objective: Psychiatric co-morbidity and attachment issues are prevalent in obese patients. A possible relationship between insecure attachment styles and eating disorder risk has been proposed. The aim of this study is to determine the psychiatric co-morbidity, attachment styles and related risk factors in obese patients. Method: Obese patients with body mass index of 30 kg/m(2) or higher and non-obese controls matched for age, sex and education were included with a total sample of 173 participants. Diagnostic assessment using Structured Clinical Interview for DSM-IV Axis I Disorders and the Adult Attachment Scale, Hamilton Depression and Hamilton Anxiety scales were carried out. Attachment styles were classified as-anxious/ambivalent, avoidant and secure. The anxious/ambivalant and avoidant groups were combined and compared with the secure group. Results: Fifty three (40.8%) obese patients had psychiatric disorders including major depression (n=44; 33.8%). Anxiety was found to be a risk factor with obesity and BMI in both patients with or without any psychiatric co-morbidity. Psychiatric co-morbidity was significantly higher in obese patients (40.8%) than controls (18.6%). 55.4% of the participants had insecure attachment styles, it was significantly higher in obese patients. Insecure attachment styles were higher with psychiatric co-morbidity. Discussion: Psychiatric co-morbidity and insecure attachment styles were prevalent in obese patients, and the symptom of anxiety was found to be a predictor of obesity and body mass index. Psychiatric examinations including attachment styles and anxiety will help to advance better treatment strategies for obese patients.