Abstract
This paper focuses on improving and build a discrete event simulation model for modeling outpatient pharmacy workflow queuing system with the intent of exploring options for designing an efficient the queuing system of KKUH outpatient pharmacy Riyadh KSA. Simulation models of existing workflows in the pharmacy for KKUH outpatient pharmacy were created using discrete event simulation software (Arena). The data is collected for each server containing seven servers. Model inputs included prescription arrival times and processing times for each Server, Baseline of model is the predictions of prescription turnaround times, were then compared to those observed in reality. Various scenarios were tested and the results compared to those of the baseline models. The result found from the simulation model shows that a long waiting time exist in the system. The basic purpose of simulation model is to reduce the patients' waiting time and enhanced the quality of services.