The current study aimed to find the relationship between attention, relevance, confidence, and satisfaction (ARCS) learning motivation and class effectiveness inherent in problem-based learning (PBL) classes designed for dental and nursing students. Seventy-nine participants responded to survey items for motivation and class effectiveness after completion of their classes. The study findings were as follows. First, the differences among the dental**, clinical**, and nursing** PBL classes were identified in terms of class effectiveness (F=3.63, p<0.05) and academic achievement (F=13.9, p<0.01). Second, three learning motivation factorssatisfaction (t=4.07, p<0.01), confidence (t=2.84, p=0.01), and relevance (t=2.96, p<0.01)-appeared to determine class effectiveness in the abovementioned order. Only attention (t=2.02, p=0.05) was significantly related to academic achievement. Third, the relationship between hours of learner contribution to the PBL tasks and academic achievement was statistically significant. Therefore, we suggest the incorporation of ARCS motivation factors in PBL classes on the basis of the characteristics of each major and grade.