The preferred viewing distances for high definition television LCDs were measured as a function of the screen size, screen luminance and content of the displayed pictures. Although the screen size is the most dominant parameter, both it and the screen luminance significantly influence the preferred viewing distance, while the content of the displayed pictures does not. The ratio of the viewing distance preferences to the screen height (H) decreases with the size of the screen. The preferred viewing distance for a 24-inch display is a 5.9 H for a screen luminance (peak white luminance) of 200cd/m2. Similarly, that for a 65-inch display is a 3.9 H. The preferred viewing distance for a screen luminance of 200cd/m2 can be described Using the following empirical equation: D = (2.73 S + 75) /S. This is where D is the preferred viewing distance in screen height and S is the diagonal screen size in inches, where S is larger than or equal to 24 and smaller than or equal to 65. In this paper, these results are compared with the field survey data of the practical viewing distances in home environments. We also discuss the optimum screen size and viewing conditions of high definition television LCDs in actual home environments.