In the process of working through evaluation of efforts to transform undergraduate laboratory experiences at our institution, we developed a protocol for observing laboratory learning environments that could be used in varying institutional contexts. We began using the Instructional Practices Inventory and found many strengths in this protocol but saw the need to make modifications to better account for the nature of science laboratory course environments. The resultant protocol, the Laboratory Instructional Practices Inventory, directs observer attention to forms of student engagement and discourse. By categorizing the most predominant forms of engagement and discourse at discrete time points throughout laboratory sessions, observers and instructors can empirically document major trends in the learning environment. These data can then be used to inform modifications to curriculum and/or pedagogy to better meet the goals of the course. (Contains 2 tables and 3 figures.)