Economic analysis ofmicrobiological controlinan Advanced Therapy Unit. The Advanced Therapy Division of a pharmaceutical company, produces two different products based on mesenchymal stromal cells. The application of these products includes primarily osteoarthritis, pain relief and regeneration of cartilage and bone. Given the nature of the products and that they are injected into patients, microbiological controls in raw materials, product in process, final product, supplies, facilities, equipments, air and operators must ensure the limits of the Colony Forming Units (CFU) number defined in each point. To assure it, many and various microbiological controls, most of them outsourced to approved suppliers, are run. However, complexity in order to properly allocate the costs of such monitoring to the Department of Advanced Therapy and consequently deficient cost control, is detected. To solve this, it is proposed to design a spreadsheet that will allow the control of the current costs and that can be flexible to include changes of different nature and therefore adapt to other companies. The final spreadsheet reflects that the projected costs for 2013 related to external suppliers practically achieve € 94,000, with a figure of consumables around € 16,600 for a total of approximately 5,600 controls. After analyzing the information obtained, it is established that internalizing some of the controls, may exceed the € 40,000 annual savings in a first step. The implementation of internalization yields in 2013 to a total saving of € 18,000, being the forecast for year 2014 of around € 40,000. At the end of the project, further possible savings alternatives are presented.