If clinical decisions are made on the basis of biased data, the decisions may be biased also and may result in ineffectual or harmful decisions and actions. One source of bias is missing data. A variety of procedures exist for dealing with missing cases. Subject nonresponse—when all data are missing for the subject—has been discussed in research methods texts and articles. However, less is known about methods for treating missing data within records, or item nonresponse. Also, social work research methods texts have failed to systematically describe and compare various approaches for treating item nonresponse. Several procedures for treating item nonresponse are outlined in this article, and guidelines are suggested for selecting a procedure.