Introduction: Indonesia faces a nutritional transition driven by rapid urbanisation, economic growth, and advanced technology. It has reduced work-related energy expenditure and changed workers' eating habits. Workers often mistime their food intake and eat improperly, especially during their first meal. These conditions can increase obesity, metabolic syndrome, non-communicable diseases (NCDs) and finally, lower workers' productivity. Investigating the habits at the first intake may help find solutions. However, research on the first intake in Indonesia is scarce. Thus, this study aims to investigate first intake and its related factors among Indonesian worker. Materials and methods: A quantitative cross-sectional study using secondary data analysis from the 2018 Indonesian Food Barometer (IFB) was conducted. It included 894 Indonesian male and female workers (excluding housewives, students, and retirees) aged 18 to 64 years. Data on the first intake was collected using 24-hour recalls. The Chi-square test and binary logistic regression (p-value<0.05) were employed to assess the relationship between sociodemographic, nutritional status, day of intake, and first intake. Results: The study found that first intake was associated significantly (p<0.05) with age, marital status, wealth index, ethnicity, and day of intake; however, in all dimensions, the age factor was the dominant factor associated with first intake. Conclusion: The study showed age was the dominant factor of first intake, and further intervention and health promotion, especially related to breakfast habits among workers, should take age into consideration. © 2025 Universiti Putra Malaysia Press. All rights reserved.