The objectives of this research were to study the level of moral reasoning amongst business students and to study the connection of moral reasoning to demographic characteristics (gender, education level, major in university, GPA, religious affiliation, and household income). Lawrence Kohlberg's theory of cognitive moral development (CMD) was the main theory used for this study. The respondents were 400 undergraduate business students from Kasetsart University, Thailand, comprising 5 business majors - finance, management, operations management, marketing, and accounting. A questionnaire was adapted from and based on the Moral Judgment Interview, created by Kohlberg (1969) and his associates, and the Defining Issues Test, created by Rest (1979), to measure different levels of moral reasoning through 10 business dilemmas. Measures of central tendency, mean score and dispersion, analysis of variance t-test, f-test, ANOVA, and Post Hoc were utilized to analyse the data and test several null hypotheses by using the computer program SPSS for Windows. The results indicated that the majority group of business students at Kasetsart University were in Stage 4, the stage of authority and social order maintaining orientation, as based on Kohlberg's Moral Reasoning Theory.