Condition monitoring of the machining process is very important in today's precision manufacturing, especially in the electrical discharge machining (EDM). This paper introduces a fuzzy-based algorithm for prediction of material removal rate (MRR), tool wear ratio (TWR), and surface roughness (Rz, Rk) in the EDM and ultrasonic-assisted EDM (US/EDM) processes. In this system, discharge current, pulse duration, and ultrasonic vibration of tool are the input variables and outputs are MRR, TWR, Rz, and Rk. The proposed fuzzy model in this study provides a more precise and easy selection of EDM and US/EDM input parameters, respectively for the required MRR, TWR, Rz, and Rk, which leads to better machining conditions and decreases the machining costs. The fuzzy modeling of EDM and US/EDM were able to predict the experimental results with accuracies more than 90%.