Background: Previous research using nationally representative data showed significant differences between primary care physician (PCP) and oncologists’ attitudes and practices with respect to care of cancer survivors and called for more effective communication and coordination to improve care. This study compared PCP and oncologists’ attitudes and practices for follow-up cancer care within an integrated health system sharing a common electronic health record and clinical infrastructure to examine whether the integrated setting facilitated communication and coordination between PCPs and oncologists. Methods: 41 PCPs and 24 oncologists (response rate = 52%) affiliated with an integrated safety-net health system completed a validated survey. The survey assessed PCP and oncologists’ preferred models for delivering care, attitudes towards follow-up care, and cancer surveillance practices in this setting. Results: 41% of PCPs preferred an oncologist-led care delivery model as compared to 21% of oncologists. More PCPs than oncologists (73% vs 58%) agreed that PCPs have the skills necessary to initiate cancer surveillance. Yet, PCPs more often disagreed (56% vs 42% of oncologists) that they should have primary responsibility for providing cancer follow-up care. PCPs and oncologists differed significantly over cancer surveillance practices. Oncologists more consistently reported that PCPs ordered tests for cancer surveillance, evaluated patients for cancer recurrence and for adverse physical and psychological effects of cancer or its treatment, as well as managed pain and adverse outcomes of cancer treatment. PCPs, however, did not report equivalent ordering for these services. Conclusions: Even within an integrated health system, we found significant uncertainty as to who is responsible for care of cancer survivors. Oncologists more commonly assigned responsibility for cancer survivorship care to PCPs than PCPs recognized. This imbalance indicates many cancer survivors may not be receiving recommended care. Consensus guidelines are needed to delineate shared responsibilities for cancer survivors between primary care and oncology specialty care physicians.