Factors affecting students' grades in principles of microeconomics and macroeconomics students are analyzed from the data collected in two public universities. Results indicate that gender, number of hours worked, SAT scores, number of missed classes, recommending the course to a friend, instructors, being a junior, number of economics courses taken, course, and interest in the course, were significant factors contributing to learning and success as measured by grades. Moreover, GPA, age, staying in university housing, number of mathematics classes taken, instructor's use of graphs to explain a topic, being a fourth year student, enrolling for a class because of the reputation of an instructor had positive effect on students grades, while the effect of the number of hours per week spent on studying for the class was negative.