An accurate therapeutic diet can help people improve their medical condition. Any discrepancy in this regard could jeopardize a patient's clinical condition. This study was aimed to determine prevalence of dietary errors among in-patients at an international private hospital's food department, and to explore causes of error to suggest strategies to reduce such errors in the future. Thus, a sequential explanatory mixed-methods study was carried out. For the quantitative part, secondary data were collected on a daily basis over one-month. For qualitative data, errors arising during the meal flow process were traced to the source on the same day of error followed by qualitative interviews with person responsible. Quantitative data were analyzed in SPSS v.25 as percentages. Qualitative data were analyzed by deductive-inductive thematic analysis. Out of a total of 7041 diets, we found that only 17 had errors. Of these, almost two-thirds were critical. Majority of these errors took place during diet card preparation (52.94%), by dietitians (70.59%), during weekdays (82.35%), breakfasts (47.06%), and in the cardiac care ward (47.06%). The causes identified through interviews were lack of backup or accessory food staff, and employee's personal and domestic issues. It was concluded that even though the prevalence of dietary errors was low in this study, critical errors formed majority of these errors. Adopting organizational behavior strategies in the hospital may not only reduce dietary errors, but improve patients' well-being, and employee satisfaction in a long run.