Background and Objectives: Kidney transplant recipients are at increased risk for adverse safety events related to reduced renal function and polypharmacy. Health information technology tools have a precautionary role in improving safety in patients with kidney transplants who are at risk of drug-drug interactions. Materials and Methods: Usability testing of a drug-drug interaction inquiry system on a convenience sample of kidney transplant patients and their family members was conducted between January and April 2013 by a single interviewer. Each participant was provided with 35 tasks to complete on a cell phone with a manual keypad. The tasks were classified according to how it was completed: easily completed, noncritical error, or critical error (where a participant was unable to complete the given task without intervention by the interviewer). The final task was timed using a stop watch. Results: Out of a total of 16 volunteers, 15 completed the testing. The median time to complete the final task was 4 min (range: 2-9). In a cumulative total of 525 tasks, 33 critical errors were noted. Twelve participants had one or more critical errors. The most frequent critical errors were related to typing and spelling mistakes. Twelve out 15 participants were able to complete the final task without any critical errors. Conclusions: Understanding transplant patients' preference in technology use and adapting applications to a variety of technological portals will ensure the most effective use of targeted interventions in patient safety, particularly when applied to preventing drug-drug interactions.