This report presents the results of a study of eighth-grade science teaching, conducted as part of the Third International Mathematics and Science Study (TIMSS) 1999 Video Study. The Video Study is a supplement to the TIMSS 1999 student assessment, a successor to the TIMSS 1995 student assessment. The TIMSS 1999 Video Study had the broad purpose of investigating and describing teaching practices in eighth-grade mathematics and science in a variety of countries. Results for the science portion are presented in this report and in a summary document entitled "Highlights From the TIMSS 1999 Video Study of Eighth-Grade Science Teaching (Roth et al.2006)." The TIMSS 1999 Video Study of science teaching included the participation of five countries: Australia, the Czech Republic, Japan, the Netherlands, and the United States. It had the following broad objectives: (1) Develop objective, observable measures of classroom instruction that can be quantified appropriately to develop indicators of eighth-grade science teaching practices in each country; (2) Describe patterns of science teaching practices within each country; and (3) Compare science teaching practices between countries and identify similarities and differences in lesson features across countries, with a focus on differences between higher and lower-achieving countries. Building on the interest generated by the TIMSS 1995 Video Study of mathematics teaching, the TIMSS 1999 Video Study of mathematics and science teaching had a final objective regarding effective use of the information: (1) To develop methods for communicating the results of the study, through written reports and video cases, for both research and professional development purposes. The results of the TIMSS 1999 Video Study Science suggest characteristic patterns of eighth grade science teaching in each of the participating countries and are suggestive of the potentially important role of content and a core instructional approach in student learning and achievement. (Contains 5 chapters of tables.) Appended are: (A) Sampling, Data Collection and Coding, Reliability, and Statistical Analyses; (B) Participants in the TIMSS 1999 Video Study of Science Teaching; (C) Standard Errors for Estimates Shown in Figures and Tables; and (D) Definitions of Constructs and Variables Used in Analyses. [This report was also produced by LessonLab Research Institute.]