The purpose of this study was to investigate the relationship between HMR use and eating habits in young Korean adults. This cross-sectional study was conducted on 575 adults (232 men, 343 women) in their 20s and 30s in Korea. Their use of HMRs (classified as ready-to-eat, ready-to-cook, and fresh convenience foods) and eating habits were surveyed. The main reasons for HMR use by men and women were convenience (54.7%, 64.4%) and promptness (24.2%, 24.2%), respectively. The most frequent place for HMR purchase was a convenience store (74.1% and 65.0%, respectively). Regarding the frequency of HMR use, 1~2 times a week was the highest for ready-to-eat (40.9%) and ready-to-cook (30.1%), while no eating was the highest for fresh convenience foods (41.0%). HMR preference was the highest (3.8 out of 5 on a 5-point scale) for ready-to-eat, followed by ready-to-cook (3.3 points) and fresh convenience foods (3.3 points). The use frequency and preference of total HMRs, ready-to-eat foods, and ready-to-eat foods were positively correlated with unfavorable eating habits, including unbalanced eating, overeating, salty eating, spicy eating, skipping, and irregular meals. However, fresh convenience foods showed negative correlations with unbalanced eating, overeating, and salty eating. The use frequency and preference of total HMRs, ready-to-eat foods, and ready-to-cook foods were positively correlated with undesirable eating habits. However, fresh convenience food showed a negative correlation with eating habits such as unbalanced, overeating, and salty eating. These results should be considered for favorable food production and consumer guidance to promote healthy food choices.