Lean Thinking has been one of the preferred approaches to improve healthcare processes in developed countries; however, it has been barely used in Latin America. This study presents a Lean implementation in a Mexican public academic medical center. The goal was to reduce the time required to discharge patients from the Internal Medicine Department. This non-experimental intervention study measured, analyzed, and improved the process flow through a time study, value-added/non-value-added analysis, and the four-step quick changeover approach. Once changes were implemented, inferential statistics were used to compare results. Lean implementation allowed reducing the time to discharge patients from 6 to 3 h by eliminating 57% of non-value-added activities and 70% of errors found in discharge orders. This represents a 2% annual capacity increase and a 6.423 h bed made available without investment. Other findings include barriers regarding untrained staff about process improvement and departmental barriers and a successful quick changeover implementation. This is one of the handful of implementations of Lean Healthcare in Latin America. Furthermore, this is one of the very first studies that showcase the implementation of the quick changeover approach in healthcare. Further research should focus on the long-term impact and how the specific environment encourages/discourages future implementations.