Discharge communication between inpatient and outpatient physicians is often an inefficient and error-prone process. Adverse events result from poor communication at the time of discharge. The objective of this study was to describe development of discharge software to overcome communication barriers. The secondary objective was to assess factors that influence the time to complete tasks with the software. Methods were a performance improvement model and database analysis of 336 discharges. Software design specifications included computerised physician order entry, immediate utility, minimal development and deployment costs, acceptability to physician-users, and satisfaction of primary care physicians, patients and pharmacists. Design features included simple 'just-in-time' prompts and point-of-care prescribing resources. The dependent variable for analysis was physician time to complete discharge prescriptions and instructions while using the software. General linear and mixed-effects regression models adjusted for physician effects and other predictors. Results revealed that physician factors significantly affected the time to complete a discharge while using the software. As the number of accesses (log-ins) and free text typing increased, then time to complete the computerised discharge increased. Patient-related factors that increased physician time were discharge diagnoses, prescriptions and length of stay. In conclusion, discharge software can help inpatient physicians transfer timely, complete and legible information to outpatient physicians, pharmacists and patients. Physician and patient factors influence the time to complete discharges using the software.