To assess the agreement between self-perceived weight status and BMI status, calculated from self-reported height and weight, in nurses and to evaluate the relationship between weight status misperceptions and personal body weight, demographics and health status.

Cross-sectional questionnaire survey.

A large university in London, UK.

Four hundred and fifty-six student nurses and 588 qualified nurses attending university were surveyed; 355 student nurses and 409 qualified nurses completed questionnaires representing a response rate of 78 % and 70 %, respectively.

The respondents were mainly female (90·0 %), 66·5 % were white and their mean age was 31 years. Sixty-eight per cent of qualified nurses and 77 % of student nurses correctly perceived their weight status. In logistic regression, (mixed) black ethnicity (OR = 2·53, 95 % CI 1·01, 6·32), overweight by BMI (OR = 3·10, 95 % CI 1·31, 7·33) and ≥3 family histories of obesity co-morbidities (OR = 2·51, 95 % CI 1·04, 6·08) were significantly associated with misperceptions in the sample of student nurses, whereas overweight by BMI (OR = 5·32, 95 % CI 2·66, 10·67) was the only significant variable in the sample of qualified nurses.

A substantial proportion of nurses misclassified their weight status. Nurses’ misperception of weight status was related to their own BMI status, ethnic background and obesity-related family histories. Being aware of this may help nurses not only promote their own healthy weight, but also fulfil their public health role to practise weight management successfully with both patients and the public. While limitations of the sample mean that the study findings cannot be generalized, they do provide grounds for future larger-scale research.