PRRS is often referred to as the endemic swine disease with the largest economic impact, but few studies have determined the cost in nursery and grow-finish facilities. Cost was determined using records for 6 Ontario facilities, and taking into accout the cost of mortalities and reduced performance. Analysis was done on 0-6 months and 6-12 months post-outbreak, and in all-in all-out and continuous flow facilities. Nursery costs were calculated to be $2,485,831 per year, or $4.50 per pig per year, and grow-finish costs were $1,464,012, or $1.87 per pig. This is much lower than calcualted costs in another study because mortality rates and growth performance were less affected in this study/