We describe efforts to obtain access for research to 81 wetland basins on 69 farms in four zones of the Prairie Pothole Region of North Dakota, South Dakota, and Minnesota. Access was obtained to 54% of the farms in areas where land was intensively cropped and 87% of farms in areas of low cropping intensity. On average, 1.35 operators had to be contacted and 1.70 interviews were required to obtain a decision on access to a farm. On 77% of the farms, cooperators placed at least one restriction on access, most commonly requiring walking access only or notification before nighttime work. Cost of obtaining access averaged $265/farm in wages and travel expenses. No cooperators were willing to sign written access agreements. Operators rescinded access to four farms and drained three wetland basins during the first year; six of the seven sites lost were in the intensively cropped portion of a low-wetland-density zone. The difficulty of obtaining and retaining research access to privately owned wetland basins in intensively cropped areas may be related to landowner attitudes towards wetlands. Researchers may have to rely on remote sensing or consider payment for access to secure representative research sites in such areas. Unwillingness of cooperators to sign access agreements may jeopardize research by the newly formed National Biological Service and other resource management agencies.