Rapid expansion of the processing potato industry in Manitoba has increased irrigated potato production in this province. In order to ensure the long-term sustainability of this industry, information is required to develop agronomically and economically viable crop rotation systems, which maintain or enhance crop yield and quality, and soil quality, under Manitoba conditions. In response, a cooperative study jointly-funded by the Manitoba Crop Diversification Centre and Agriculture and Agri-Food Canada (Matching Investment Initiative) was initiated to evaluate the effect of crop rotation on crop yield and quality, disease incidence, weed populations, and soil properties. In 1997, the experiment was initiated on a Wellwood silt loam at MCDC-Carberry. A randomized complete block design consisting of four replicates with eighteen plots/replicate was established, and barley was seeded across the entire plot area. Soil properties, weed populations and grain yield were determined within each plot to characterize the site and to determine baseline levels. In 1998, six crop rotation treatments consisting of two 2-year, two 3-year and two 4-year rotations were established: potato-wheat, potato-canola, potato-canola-wheat, potato-oat-wheat, potato-wheat-canola-wheat, and potato-canola (underseeded to alfalfa)-alfalfa-alfalfa. As of 1999, crop rotation treatments have been in place for two field seasons. A minimum tillage approach for the non-potato years has been employed. A summary of the '98 and '99 results will be presented.