Canine parvovirus (CPV) and canine enteric coronavirus (CECoV) are often cited as causes of diarrhoea in dogs. This study aimed to determine the prevalence of CPV and CECoV in dogs presenting with severe diarrhoea to PDSA PetAid hospitals throughout the UK. A total of 355 samples were collected from the PDSA between 2006 and 2008. All samples were tested for CPV using a long range PCR and for CECoV using RT-PCR. The prevalence of CPV was 58 per cent (95 per cent confidence interval [CI] 52 to 63 per cent), with some evidence for regional variation. The prevalence of CECoV was 7.9 per cent (95 per cent CI 5.1 to 10.7 per cent). Analysis showed that animals with no history of vaccination were more likely to be CPV positive, with greatest effect in younger animals. CPV-positive animals were more likely to present with depression/lethargy than CPV-negative cases. The volume of diarrhoea and the presence of haemorrhage did not appear to be associated with the likelihood of detecting CPV. This study shows that CPV is a common finding in dogs presenting to PDSA hospitals with severe diarrhoea, and that CECoV is a less common but still potentially important pathogen. It also confirms that young and unvaccinated animals appear to be more at risk of presenting with CPV.