Since middle schools vary in their degree of implementation of middle school practices, this research was designed to compare the job satisfaction of middle school teachers with the degree of implementation of these practices. Six teachers from each of Colorado's 50 schools with the name "middle school" were randomly selected to serve as subjects of the study. The original and one followup mailing yielded 252 responses (a 74 percent return) to the Purdue Teacher Opinionaire and the Middle School Practices Index. In addition to teacher satisfaction and the degree of implementation of middle school practices, the size of the student body and a number of teacher demographic variables were also considered. Analysis of variance and correlations were used to analyze the data. The findings indicate that overall job satisfaction of middle school faculty does not vary significantly in low, medium, or high implementation schools. In high as compared to low implementation schools, teachers are more satisfied with community support, the curriculum, and school facilities; but are more dissatisfied with their teaching load. Teachers in middle-sized schools are more satisfied than teachers in large schools. Finally, low implementation schools are generally located in rural areas and have small enrollments. (Author/MLF)