In Thailand, influenza vaccine has been providing for risk groups including pregnant women based on availability of budget and voluntary basis. This study aimed to estimate the service delivery cost per pregnant woman vaccinated against influenza. Economic costs of influenza vaccination at 8 district hospitals from different regions were estimated based on the perspective of the hospital. The micro-costing approach was applied covering labor, material and transportation costs. Costs of using refrigerator, cold box, vaccine and related materials including supply chain from central procurement to district hospital were not included. The vaccination program was defined as a set of activities including planning and training, vaccine preparation, transportation to vaccination sites, screening, vaccine delivery, AEFI surveillance and reporting. The study was based on services in 2016. Seven of eight hospitals provided campaign-based vaccination. One hospital included the service in routine antenatal care clinic (ANC). The number of pregnant women received the vaccine in each district varied from none to thirty-one depending on size of the population in each catchment area and vaccine uptake. Cost per dose vaccinated was calculated by activity and total cost. Total cost per vaccinated dose was in the range of 24 - 349 Thai baht (2016 prices). Comparing to the costing template for the influenza vaccination; the FLUTool version 3.0. The major difference in this study and that of the tool was objective and scope. The FLUTool was applied for the whole national program in a public health perspective. This study was conducted in a hospital perspective. Therefore, costs of planning and training and others were only costs incurred by the hospitals (not included those of other organizations). When comparing the micro-costing approach in this study to the FLUTool, the FLUTool does not cover mobile delivery service. This might be an input to develop the next version.