In this study, the effect of web-based homework on university students' physics achievement was compared. One of the two identical sections of introductory physics course students received pen-and-paper homework done in groups while the other received web-based online homework performed individually. And then both groups' homework performance and achievements were compared by homework assignments and standardized test scores (like Force Concept Inventory and Conceptual Survey of Electricity and Magnetism). Although there was not any significant difference in standardized test score results, in the first (fall) semester, pen-and-paper homework group performed better than the web-based group; yet, the web-based homework group did better in the second (spring) semester. (Contains 3 tables.)