The aim of this study is to enhance the coating adhesion strength by optimizing the air plasma application parameters. Air-plasma treatment parameters were selected as working distance, treatment speed and pressure, while material type parameters were determined as low mean density fiberboard (MDF-1) and high-density mean fiberboard (MDF-2). Due to the low adhesion strength in water-based paint applications compared to other types of paint, water-based paint was applied to these samples. Taguchi orthogonal design and analysis of variance (ANOVA) were applied to investigate the significant parameters on the adhesion strength. Desirability function was used to determine the optimum factor levels. According to experimental design results, working distance, treatment speed, and pressure values of 8.82 mm, 60 mm/s, and 1.10 bar were determined as optimum plasma treatment parameters for MDF-1, respectively. Corresponding values for MDF-2 were 9.19 mm, 60 mm/s, and 1.06 bar. The improvement in adhesion strength was evaluated as 22% increase for MDF-1 and 16% increase for MDF-2.