The objective of the paper is to review the effects of the implementation of the Resident Assessment Instrument (RAI) on process measures (quality of care plans and staff satisfaction) and outcome measures (health problems and quality of life) in nursing homes. All available publications on the effects of the RAI were included in the review. The most positive effects of the RAI were found in improvements in the comprehensiveness and accuracy of the care plans. As regards outcome quality, the RAI method had most positive effects on the health condition of nursing home residents with diminished physical and mental functioning. In psychosocial areas of assessment, fewer positive effects were found. We concluded that positive effects have been found, based on pre-test-post-test non-controlled designs. Control-group designs are needed in future evaluation studies to determine if these positive results will hold.