The international style played a key role in modern tropical architecture in Latin America and the Caribbean, particularly in notable cases in Brazil and Colombia. In the 1950s, Colombia’s modernisation of sanitary infrastructure was reflected in the design of high-level hospitals, some of which were developed by the firm Cuéllar Serrano Gómez Ltda. (CSG) under the leadership of architect Gabriel Serrano, a prominent figure in twentieth century Colombian hospital architecture. The Social Services Institute (ISS) Clinic in Cali, stands out as an important cultural asset and one of the highest-quality health buildings in modern Colombian architecture. The building has been undergoing continuous rehabilitation and updating since its inauguration to accommodate increasing patient demand and to incorporate structural and technological advancements and regulatory requirements over time. In 1955, CSG began using the Ret-Cel concrete technology in large hospital infrastructure projects. This allowed them to address the challenges of building platform-type structures and adapt to the tropical climate and sunlight, through the design of concrete envelopes, and the use of red brick characteristic of modern Colombian architecture. Under Colombian conservation law and regulations, the clinic has a type II intervention level, highlighting significant functional modifications and raising discussions about their impact on the building’s heritage values. Municipal and departmental heritage agencies use conservation and management measures, such as the Special Management and Protection Plan (PEMP), to monitor the building’s condition and performance. The building also required internal redistribution, structural reinforcement, and the provision of highly specialised services to meet the current needs of a growing population.