The aim of this study was to explore and define the different dimensions of professional stigma attached to obese patients by dietitians. Four focus groups were conducted with 23 Israeli dietitians. Findings showed that while treating obese patients, dietitians underwent a stigmatization process involving cognitive, emotional, and behavioral phases. Obese patients with an internal locus of control, who took responsibility for their failure to diet, triggered positive feelings (e.g., pity and empathy), whereas obese patients with an external locus of control, who blamed others for their failure, triggered negative feelings (e.g., anger and frustration). Participants' emotional rejection of obese patients was manifested in three behavioral dimensions: instrumental avoidance (e.g., shorter sessions); professional avoidance (e.g., less energy and effort); and interpersonal avoidance (negative tone and evasive verbal and body language). Continuing education for dietitians is recommended to assist them in dealing with their negative feelings and behaviors toward resistant obese patients.