This study was designed to assess the teacher verbal role behavior of Guided Discovery/Inquiry before and after an in-service workshop. The sample consisted of 24 junior school teachers, who were teaching Introductory Physical Science (IPS) materials and traditional materials (non-IPS). Three IPS and five traditional teachers were randomly assigned to a one-day in-service workshop treatment group (TRT) and the other 16 teachers served as control group (non-TRT). Three pre-observations of one hour each, using the Ribble and Schultz Social-Substantive Schedule II, were systematically recorded for each teacher in both TRT and non-TRT groups. Following the workshop, all the teachers (TRT and non-TRT) were post-observed to assess any measurable changes in the verbal role behavior of the TRT teachers. The findings showed that no IPS teacher exhibited in the pre-observations the verbal role behavior of Guided Discovery/Inquiry. The in-service workshop was not totally effective in changing the verbal role behavior for TRT and non-TRT teachers. The TRT group showed significant changes toward eliciting more questions from the total class and developing an atmosphere with fewer teacher reproving/defensive behaviors for freer volunteer responses from the students. Teaching experience (more than nine years) was related to reduction in teachers' reproving/defensive behaviors in classrooms. (Author/PS)