Although a great deal of successful research has been carried out in just-in-time (JIT) philosophy, few researchers have focused on the adaptation of JIT philosophy in service systems. Despite the recent improvements in the service systems, few studies have been carried out which examine the effects of the JIT philosophy on service systems which have a different structure to production systems. As a result of the benefits obtained from successful application of the JIT philosophy in the production systems, we have adapted the JIT philosophy for the service systems and examined the obtainable benefits. For this purpose, observation and time-scaling studies were made in an Adult Emergency Service in Turkey. Within the framework of the data acquired in this study, the existing system was modeled. By analyzing the simulation results, an alternative system has been proposed which can be applied to the system. Results show that the proposed system under the principle of JIT philosophy outperforms the existing system.