Previous research has revealed that students may hold several misconceptions regarding fundamental topics of chemistry. With the idea that teachers play a critical role in diagnosis and remediation of students' misconceptions, a "course" for preservice chemistry teachers was designed. The purpose of this study was to describe the views and understandings of preservice chemistry teachers on issues related to nature, diagnosis and remediation of misconceptions in the aftermath of this specially designed "course". This course placed the collaborative, active and reflective practices of preservice teachers at its center. The data sources were self-reflection reports written by preservice teachers at the end of the "course" and high school students' answers to questions regarding some misconceptions after preservice teachers applied their lessons to these students. Results showed that the majority of the participating preservice teachers realized the importance and variety of misconceptions, as well as ways of dealing with them. Also, there is satisfying evidence that many of the high school students' misconceptions changed after the applied lessons. (Contains 5 tables.)