This study reports CO 2 laser drilling of the cover glass using the Taguchi method. In this study, the Taguchi method containing L16 (4 factors and 4 levels) orthogonal array design was employed to investigate the effect of process parameters on hole quality. Based on the results of experiments, holes with a high total hole quality index (THQI) show less cracking and heat affected zone (HAZ), and in this case the circular morphology of a hole is relatively well kept. From the Taguchi analysis, it is found that the THQI is significantly affected by laser power, however the effect of the focal position on the THQI is very small. The optimal process parameters to maximize the THQI are the laser power of 20 W, the scan speed of 20 mm/s, the scan of 1 pass and the focal position of 0 mm. The regression model to predict the THQI is obtained using the surface response method. It is confirmed that the regression model predicts the THQI with 5.717 % error (average).