Qualitative studies indicate that mathematics does not work well in e-learning. The current study used quantitative methods to investigate more objectively the extent of problems with mathematics in e-learning. The authors used student attrition as a simple measure of student satisfaction and course viability in two studies, one investigating attrition in e-learning and a second comparison study of attrition in face to face courses. In e-learning, attrition (drop out rate) was significantly higher for math courses versus non-math. For face to face courses, attrition rates for math versus non-math courses were nearly equal. The authors suggest reasons for high student attrition in math e-learning. Online student populations are different from their face to face peers. E-learning systems are poorly adapted to mathematics. (Contains 2 figures, 2 tables, and 1 endnote.)