Careful needs assessment is a prerequisite to addressing issues of health care program effectiveness and program planning from a population-based perspective. Home care program evaluation literature is lacking in examples of strategies for such assessment. A nurse-screening of admissions was conducted at an acute care general hospital to estimate need for hospital-based home care (HBHC) services among the 2,613 patients discharged from medical and surgical services over a 5--month period. After careful delineation of inclusion and exclusion criteria for identifying HBHC patients and participant-observer training, the nurse's judgments on patient appropriateness for HBHC care were shown to agree reliably with those of the HBHC staff (k = +.45). In the study hospital under current conditions, an estimated 64% of discharged patients appropriate for home care do not receive these services. A comparison of the incidence according to service of HBHC-appropriate patients and patient-referral rates to HBHC suggests that one service over-refers (neurology), but most under-refer. Screening nurse salary expenditures constitute the major costs of this approach to home care needs assessment, which is recommended only for addressing major, infrequent programmatic policy issues.