This paper examines the proposition that "timing" (of referral) is a crucial element in determining the effectiveness of the discharge planning process. A brief review of the relevant literature is followed by the description of a study undertaken to assess the impact that various impediments had upon discharge planning practice in two matched ward populations of a large, acute care university hospital. Along with timing, three other impediments were identified and their influence assessed; (a_ noncompletion of transfer forms required; (b) unavailability of an appropriate (i.e., needed level of care) bed in an approved facility; and (c) unanticipated change in the patient's medical condition. Some implications of the findings are examined and discussed, and directions for future study are identified. Appended are facsimiles of the instruments employed.