This article presents an approach that can analyze the influence of tunable screws and perform a computer-aided tuning for microwave filters. In the approach, a machine-learning model that reveals the influence of tunable screws on the filter response is first developed by least squares support vector regression, according to some data from the tuning experience of filters. Then a computer-aided tuning procedure based on the model is proposed, and the obtained adjusting amount of tunable screws can assist an unskilled operator to perform a fast and accurate tuning. The approach is validated by some experiments and the results confirm the effectiveness. The approach is particularly suitable to the computer-aided tuning of volume-producing filters. V C 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE 20: 422-429, 2010.