The purpose of this research was to ascertain the optimum rear slit length of tight skirts in terms of comfort and appearance. The typical measurements of tight skirts on current market were recorded and a questionnaire survey of women in their twenties was conducted in order to find out the current conditions of the skirts and specific complaints about motion restrictions. Just over half the respondents (50.4%) reported that they had experienced damage to the slit usually when they were stepping on a bus and also walking and running. The clothing test showed that the slit length increased as the motion went from "walking" to "going up stairs", and to "stepping on a bus" In addition the slit length significantly decreased as the hem circumference of skirt became wider. On the basis of those results, a wearing test, evaluating sensual comfort and appearance, was also conducted and the results showed that the slit length of 385mm was most prefered.