This study investigates relationships between understanding of nature of science and four key factors elementary science teachers possess, which are: (1) Their specializations in different science areas (Physics, chemistry, and biology), (2) Gender issues, (3) How long they have been teaching in elementary school environments, (4) Their perspective and suggestions to acquiring necessary knowledge and understanding of nature of science. This study is also a first part of a big research project. Four elementary science teachers participated in the study. The results showed that participants' views of the target aspects of nature of science were not significantly different according to their major disciplines (Physics, Chemistry, and Biology) but there were some significant differences according to their gender differences. Sample NOST [Nature of Science Test] items (multiple choice) are appended. (Contains 1 table.) [This paper was published in the proceedings of the 2007 Association for Science Teacher Education (ASTE) conference.]