In a hospital, doctors and nurses shares roles in treating admitted patients. Communication between them is necessary and communication errors become the problem in medical safety. In Japan, verbal instruction is prohibited and doctors write their instruction on paper instruction slips. However, because it is difficult to ascertain revision history and the active instructions on instruction slips, human errors can occur. We developed template-based computerized instruction entry system to reduce ward workloads and contribute to medical safety. Templates enable us to input the instructions easily and standardize the descriptions of instructions. By standardizing and combine the instruction into one template for one instruction item, the systems could prevent instructions overlap. We created sets of templates (e.g., admission set, preoperative set), so that doctors could enter their instructions easily. Instructions entered via any of the sets can be subdivided into separate items by the system before being submitted, and can also be changed on a per-item basis. The instructions were displayed as calendar form. Calendar form represents the instruction shift and current active instructions. We prepared 382 standardized instruction templates. In our system, 66% of instructions were entered via templates, and 34% were entered as free-text comments. Our system prevents communication errors between medical staff.