OBJECTIVE To investigate undergraduate student nurses' and registered nurses' attitudes towards obese persons and towards the management of obese patients. BACKGROUND Obesity is a global public health problem. Escalating rates of overweight and obesity are also taking a toll in Asian countries that have historically had much lower rates. Despite the growing prevalence of obesity worldwide, studies show that nurses and other health professionals hold negative attitudes towards obese people, which may affect the care of obese patients. METHODS Cross-sectional study. METHODS A self-administered questionnaire was completed by 352 undergraduate student nurses and 198 registered nurses. The questionnaire consisted of the Fat Phobia Scale, the Attitudes Toward Obese Adult Patients Scale and a demographic profile. Data were analysed using descriptive statistics and student's t-tests. RESULTS Overall mean scores on the Fat Phobia Scale (3.53 SD 0.47) indicated average levels of fat phobia and mean scores on the Attitudes Toward Obese Adult Patients scale (2.64 SD 0.51) indicated neutral attitudes towards obese patients. Registered nurses had significantly higher levels of fat phobia and more negative attitudes than did student nurses. The majority of participants perceived that obese people liked food, overate, and were shapeless, slow and unattractive. Additionally, over one-half of participants believed that obese adults should be put on a diet while in hospital. CONCLUSIONS Results of this study show that both registered nurses and student nurses have negative perceptions of obesity and are unlikely to attribute positive characteristics to obese individuals. That registered nurses hold more negative attitudes towards obese person is cause for concern. CONCLUSIONS Given the increasing prevalence of obesity and the disproportionate number of obese persons affected by many health conditions, current and future nurses should have positive professional attitudes towards obese individuals. Obesity needs to be more adequately addressed, both in basic nursing education programs and in continuing professional education for practising nurses.