Organic milk production in the UK increased from 16 million litres in 1997/98 to 218 million litres in 2001/02 (MDC, 2002). Consumers often cite health benefits of organic food as a reason for purchase (Hill and Lynchehaun, 2002; MDC, 2002). To date, only minor differences in composition between organic and conventional milk have been identified (Lund, 1991; Jahreis, et al, 1996; Toledo, et al, 2002), with little information available about organic milk from the UK. However, differences in farm management and cow nutrition in the organic system may potentially affect milk composition and milk hygiene. The aim of this project was to compare the composition (including fatty acids and vitamins), hygiene and persistent organic pollutant (POP) content of milk from UK organic and conventional farm-gate and processed milk. Additionally, farm management data were collected to identify factors affecting milk composition.