The objective of this study was to develop empirical functions in order to predict vacuum fluctuations in b and d-phase and in claw using response surface methodology (RSM) and to verify the optimum points and the mathematical models for both, conventional and quarter individual milking system. The independent variables considered in the study included the system working vacuum, the pulsation rate and ratio and the milk flow rate. Experiments based on the central composite design (CCD), one of the designs in RSM, were conducted in the laboratory using water and artificial teats. The data obtained were then used to develop functions in polynomial form that allowed predicting the vacuum fluctuations in claw for conventional system and junction point in quarter individual milking system, b and d-phase for both systems. Optimum point for system working vacuum was obtained for both systems and it was found to be 38.9 and 39.7 kPa for conventional and quarter individual milking systems, respectively. The fluctuation models obtained from the study indicated the complexity of the fluctuation phenomena in milking systems. But, it is believed that the models developed may be used for the design of conventional and quarter individual milking system for a better performance.