The study investigates the mathematical and the pedagogical content knowledge among in-service and pre-service first- and second-grade mathematics teachers. The sample of 300 subjects consisted of 150 first- and second-grade in-service teachers and 150 pre-service teachers studying in a college of education, 75 of whom were first-year students and 75 third- and fourth-year students. The data was collected using two tools--a mathematical content knowledge (MCK) test and a mathematics pedagogical content knowledge (MPCK) test, the items on each of these representing the four sub-domains studied in first- and second-grade: numbers, arithmetic operations, geometry/measurements, and word problems. The principal findings of the study indicate that all three groups possess limited knowledge of both MCK and MPCK in all sub-domains. The in-service teachers achieved the highest mean in the MCK and MPCK and the differences between the in-service teachers and the two groups of pre-service teachers were statistically significant in general MCK and MPCK and in all the domains. Moreover, the lowest MCK mean was in the geometry/measurements domain, and the lowest MPCK mean was in the word-problems domain.