OBJECTIVE: To identify and compare suggested food portion sizes in UK schemes. DESIGN: The study collated and compared suggested portion sizes from selected UK schemes intended both for general advice and weight-loss advice. SETTING: Portion size schemes were included if they were relevant to the UK, provided actual portion size information, were intended for adults and were obtainable from the public domain in November 2010. Included schemes were from the food industry, non-governmental organisations and health-care professionals. Suggested portion sizes of foods occurring in at least one scheme for general advice and at least one scheme for weight loss were included. Own brand on-pack portion size labelling from a large UK-wide supermarket was added to represent portion size advice from UK food retailers. SUBJECTS: Not applicable. RESULTS: The suggested portion sizes in the weight-loss advice schemes were often concordant, as were the general advice schemes, except one general advice scheme from a non-governmental organisation which was more closely aligned with the portion sizes for weight loss. Overall there were substantial discrepancies between suggested portion sizes for muesli and crunchy breakfast cereals, rice, pasta and potatoes, meat, fish and pulses, whereas portion sizes for cooked vegetables, dried fruit, some breakfast cereals and cheese were broadly consistent. CONCLUSIONS: There is a lack of consistency in the portion sizes communicated to the public. An independent and authoritative scheme of suggested portion sizes for all foods, with distinct recommendations for general advice and for weight-loss advice, could be of benefit.