Available professionally designed systems for recording, storing, retrieving, and analyzing patient data (such as treatments delivered, laboratory and pulmonary function test results, ventilator settings, and patient assessments) are prohibitively expensive to many hospitals and clinics. At Tufts-New England Medical Center we designed and implemented a computerized patient data management system that uses relatively inexpensive "personal digital assistants" and inexpensive, commonly-available software. Compared to the pen-and-paper flow sheet system we previously used, our computerized system saves time and money, is accurate and user-friendly, and allows data retrieval and analysis that can improve clinical practice and efficiency. We believe our experience could benefit other institutions.