Web 2.0 technologies support learner-centered instruction that includes interaction, feedback and social relationships (Boyd, 2007). The assessment of student activities using Web 2.0 (Gray et al., 2010), however, poses a challenge for instructors who perceive benefits to student learning and wish to integrate these technologies into formal instruction. Semi-structured interviews were conducted with instructors (n=12) to identify how they assess student learning when students use social media in their university courses. Qualitative data analysis by two coders indicated that the course objectives, anticipated learning outcomes and the instructor’s teaching philosophy influenced their decisions about the type of assessment used. Some instructors considered timely participation and regular student engagement as sufficient to award the highest grade while others used detailed rubrics for critical thinking, participation, peer interaction, and quality of student contributions. Challenges faced by instructors included their students’ unfamiliarity with social media, the time needed to “keep up” with students’ online activities, and confidentiality of student data. In this presentation we will discuss the assessment challenges faced by instructors who use Web 2.0 in higher education and share a pilot survey about instructor assessment of social media that is based on the qualitative data.