BACKGROUND/OBJECTIVES: The food frequency questionnaire (FFQ) is a commonly used tool for assessing the usual diet of groups and individuals. This study developed a chatbotbased mobile FFQ, embedded within KakaoTalk, Korea’s most popular mobile instant messenger. This study compared the energy and nutrient intake reported by participants using a chatbot versus a paper-based FFQ. SUBJECTS/METHODS: This study included 95 participants (50 men and 45 women, aged 24–79 yrs) who underwent gastroscopy or colonoscopy for cancer screening at Dongguk University Ilsan Hospital between April and August 2022. The participants completed both the chatbot and paper-based FFQs within a 3-mon period. The comparability of the chatbot-based FFQ with traditional paper-based FFQ was examined by comparing the log-transformed intakes of energy and nutrients using Pearson correlation coefficients.The Cohen’s Kappa coefficients, Bland–Altman plots, and cross-classification percent agreement were used to evaluate the compatibility. RESULTS: The Pearson correlation coefficients of energy and energy-adjusted nutrients ranged from 0.74 (niacin) to 0.90 (vitamin A), with a median coefficient of 0.85. The Cohen kappa coefficients varied from 0.42 (niacin) to 0.64 (n-6 fatty acid). The Bland–Altman plots suggested that most of the data points fell between the lower and upper limits of agreement, and 88% to 98% of the participants were classified into the same or adjacent quartiles for energy-adjusted nutrients. CONCLUSION These findings indicate good comparability between chatbot- and paperbased FFQs. A chatbot-based mobile FFQ can provide comparable dietary intake rankings, making it a viable tool for evaluating the associations between diet and various disease risks in longitudinal studies.