Can we use the methods of Web usability testing to learn about library instruction? This article is among the first in the field trying to establish a link between usability and instruction. The author discusses useful insights that Web usability can bring to our pedagogy as well as to the efficiency of library instruction. The result of a Web usability study conducted at LaGuardia Community College in 2005 are examined. Findings suggest direct relationships between what is being taught in library instruction sessions and how students browse and search library resources. The author discusses vocabulary test results and draws some parallel with students' success at finding information on the library Web site. Finally, a conceptual model of library instruction assessment through usability studies is presented. The author hopes to provide an innovative approach to library instruction assessment. (Contains 4 tables, 2 figures and 38 notes.)