This study investigated the impact of the New Jersey Writing Project in Texas (NJWPT) three-week professional development in writing instruction on teachers' attitudes toward writing and the teaching of writing. In addition, the research explored the impact of teacher attitude on the classroom implementation of writing strategies. Therefore, the findings have the potential to provide information regarding delivery of professional development that will enhance teacher effectiveness and positively impact students' writing achievement. The study utilized a pre-experimental design employing mixed methods with no control group. Separate paired t-tests were used to analyze teacher responses on the Emig-King Attitude Scale for Teachers (King, 1979) with pre-training and post-training responses, and with post-training and post-implementation (two years after training) responses. Quantitative findings revealed that questions in multiple categories showed statistically significant differences (p less than 0.05) in attitude from pre-training to post-training. There were no significant differences in attitude two years later when the post-implementation scales were analyzed. Furthermore, quantitative data were collected regarding the frequency of implementation of writing strategies in the classroom using a Self-Assessment Implementation Survey (Eads, 1989). The top four ranking strategies implemented, in class writing, prewriting, journal writing, and teacher writing with students, were strategies implemented on a daily basis during the three-week NJWPT professional development (Carroll, 1979). To gain a deeper understanding of the impact of the professional development on the participants in the study, teacher interviews were conducted with key informants four years after training. Themes and categories were identified. These qualitative data indicated that the NJWPT professional development had a positive impact on teacher attitude toward writing and the teaching of writing and influenced the frequency and type of writing strategies the teachers implemented in their classroom. Both quantitative and qualitative data sources were used to describe the impact of the professional development on attitude and implementation, as well as the relationship between teacher attitude and frequency of implementation of writing strategies in the classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]