This study develops Korean Style Loungewear as a cultural fashion product. Through the use of surveys, Korean sentiments about Korean traditional clothing and Korean style fashion have been examined. The survey was conducted for 5,000 people in Korea; 3,500 responses of meaningful data were statistically analyzed. The data was processed by a SAS system; frequency and percentage were performed. It was found that Korean people have a high preference for Korean traditional clothing; however, they are not satisfied with its comfort, maintenance, or price. They answered that they would wear Korean style fashion if the design, comfort, and price were improved. They responded positively on the development of Korean Style Loungewear and its effectiveness as a cultural product. Based on the survey and basic geometric structures of Korean traditional costumes, silhouette designs of Loungewear have been developed. The designs are divided into one-piece styles and two-piece styles. The characteristic design details are git (Korean neckline) and goreum (Korean tie ribbon). The results have been shown on the "Han Style Fashion Show" by Jeonju City and exhibited in the "Seoul Living Design Fair" and the "International Art & Craft Trend Fair" in COEX, Seoul.