The aim of this thesis is to describe how the forecasting process works in an electrical components company and to propose improvements in order to strength and make more efficient the process itself. As forecasting is part of the S&OP (Sales and Operation Planning) there are several factors (inputs) that might influence it. In this work we are going to focus on improvement in the preparation of the forecast that have to be sent to suppliers. This step of the process is usually less structured than other steps such as the DRP (Distribution Requirement Planning) and indeed, there is room for improvement in the way to collect data, in how to aggregate them, in the amount of information one want to send to supplier and in the modality to send the signals.