BACKGROUND Communication between inpatient pediatric hospital medicine (HM) and primary care providers (PCPs) is important for quality care. As provider workload increases, it is important to focus on a means to improve communication efficiency. Our goal was to increase the percentage of HM admissions using 1-way communication from 0% to 35% over a 16-month period. METHODS HM providers and PCPs collaborated to identify 12 admission diagnoses for which 1-way communication could be used. Using quality improvement methods, we studied the implementation of “Leave a Message” (LAM) calls for 1-way communication and providing PCPs with the option to place a return call. Control charts were used to track LAM call use and balancing measures of PCP return phone calls, additional PCP communications, and 7-day readmissions over time. RESULTS A total of 778 LAM calls were placed by HM providers over 16 months. The percentage of LAM calls out of all PCP calls placed ranged from 0% to 35% during this time, increasing significantly during winter months and before the coronavirus disease 2019 pandemic. Only 0.4% (n = 3) of LAM calls were returned by PCPs. Estimated PCP return phone calls were reduced by 11.1 calls per week. CONCLUSIONS We created a system for 1-way telephone communication between HM providers and PCPs for common, simple admissions and reduced the need for PCP return phone calls. The low percentage of LAM calls returned by PCPs may suggest that 1-way communication is adequate for most simple admissions.