The morbidity and mortality associated with several large outbreaks of gastrointestinal diseases caused by Shiga toxin-producing Escherichia coli (STEC) indicating the threat of these organisms to public health (1). These are commonly recovered from food animals and were found responsible for severe gastrointestinal and systemic diseases such as haemorrhagic colitis (HC) and haemolytic uremic syndrome (HUS) leading to diarrhoea, especially among the infants in the developing countries (1,2). STEC strains produce one or both of two major types of Shiga toxins, designated [Stx.sub.1] and [Stx.sub.2]. The [Stx.sub.2] is associated with an increased risk of developing HUS (3). Although, in India, reports are available on isolation, identification and characterization of STEC in human and animals (4-10), there appears to be no information on association of STEC in poultry. An outbreak of acute diarrhoea in broiler chickens aged 6-8 wk was reported in Aizawl, Mizoram in 2007. We investigated this outbreak for detection and characterization of pathogenic organism in the broiler chickens with diarrhoea.