Medical Devices are essential for medical services. It is very necessary to manage them to be ready for quick responding on the demand of the patients that can be urgent. The case study is a Medical Device Distribution Center in Thailand and its major task is to manage medical devices for its clients starting from receiving to shipping. For the inbound logistics process, there are two types of receiving products. The first type is Goods Receive, which is to receive new products. The second type is Goods Return, which is to receive the returned products from customers. The received products will be sent to five different departments. Each department has a different amount of incoming products for each day. The inequality workload clearly affects the inefficiency of the inbound logistics process. This research is then conducted to reduce the lead time of the inbound logistics process. Discrete event simulation modeling using ARENA was utilized to allocate workers in the inbound process. The new worker allocation plan can reduce the average total inbound logistics process time for all product groups. Moreover, the average utilization of each worker is about 30%-40%.