This study investigated the rates and reasons for breakfast skipping according to gender, age, and lifestyle related factors in Korean adults. The survey was conducted using questionnaires and the subjects included 1148 male and female adults aged 19-64. The rate of breakfast skipping (frequency of eating breakfast under 4 times/week) was 41.20% of the total subjects. The breakfast skipping rate of the male subjects was significantly higher than that of the female subjects (p < 0.001). As age and household income decreased, the breakfast skipping rate increased. Residents in small cities more frequently skipped breakfast than those in larger cities. The main reason for breakfast skipping was "lack of time for the preparation and consumption of food" and this reason was especially higher for office workers and younger adults among the participants. In addition, the proportion of habitual breakfast skippers increased with age. Among the answers regarding the person who prepares breakfast in their households, the highest proportion was for "family members" in the males and "myself" for the females. Of breakfast skippers, 77.63% answered that they consumed breakfast substitutes such as breads, dairy and fruits/vegetables. To summarize the results, the gender, age and lifestyle factors of adults were significantly related to the rates and reasons for breakfast skipping. Therefore, to reduce breakfast skipping in Korean adults, a differentiated nutritional education approach relative to gender, age, and lifestyle is needed along with the development of balanced breakfast substitutes.