Previous investigations on Piagetian cognitive levels among college students both within and across academic disciplines have not addressed the issue of possible differences in cognitive levels between traditional undergraduates and older returning students. Piagetian cognitive levels were studied among traditional- and nontraditional-age college business and education majors to examine levels of cognitive reasoning in the two groups. The Arlin Test of Formal Reasoning (ATFR) was administered to 69 business majors, 114 elementary and secondary education majors, and 34 science education majors. Scores on individual tests were classified into concrete, transitional and formal levels of cognitive reasoning according to performance across eight reasoning abilities or formal schemes. These are complex thought processes identified by Piaget as developing during the middle teens. They take the following forms: multiplicative compensations (volume); correlations; probability; combinatorial thinking; proportion; momentum; equilibrium; and frames of reference. ATFR scores were also analyzed by age, business, business or education major, and gender. Results indicated significant differences across age groups in the level of cognitive reasoning abilities and between males and females, but no significant differences between academic majors. Findings suggest a need for revisions of teaching methodologies for both secondary and college level courses, with an emphasis on problem solving and conceptual skills. Includes 21 references (LPT)