Background/Context: In order to develop effective strategies for retaining able and committed teachers, it is important to understand how new teachers experience their work with their colleagues. A previous qualitative study conducted by the authors and others presented a conceptual framework for understanding new teachers' experiences of the professional culture of their schools. The prior work suggested that new teachers might be more likely to stay in teaching and remain at their schools when they work in what the authors called integrated professional cultures, which promote frequent and reciprocal interaction among faculty members across experience levels; recognize new teachers' needs as beginners; and develop shared responsibility among teachers for the school. Focus of Study: This study uses the concept of integrated professional culture to frame an inquiry about new teachers' experiences at their schools and with their colleagues. Research Design: The study examines the experiences of a representative random sample of 486 first- and second-year teachers surveyed in four states (California, Florida, Massachusetts, and Michigan). Participants were chosen using two-stage stratified cluster sampling. The mail survey achieved a response rate of 65 percent. The authors conducted descriptive analyses of the questionnaire data and summarized new teachers' experiences in a series of comparative tables. Conclusions/Recommendations: The data revealed that many novice teachers report that their work is solitary, that they are expected to be prematurely expert and independent, and that their fellow teachers do not share a sense of collective responsibility for their school. In integrated professional cultures, new teachers interact with experienced colleagues in an ongoing way. However, the authors found that approximately one-half (in CA and MI) to two-thirds (in FL and MA) of new teachers generally plan and teach alone. In integrated professional cultures, new teachers are recognized as novices and offered extra assistance; however, the authors found that less than one-third (MI) to less than one-half (CA) reported that extra assistance was available to them. Finally, in integrated professional cultures, teachers share a sense of collective responsibility for the school. However, less than half of the new teachers in the four states reported that teachers share responsibility for the students in their school. Taken together, these findings reveal that many new teachers work without the support of integrated professional cultures. Given these findings, the authors discuss in detail what policymakers and school leaders can do to address the critical challenge of supporting new teachers.