Background. It is unclear how oncologists' attitudes toward end-of-life (EOL) care affect the delivery of care. The present study examined the association between oncologists' EOL care attitudes and (a) timely specialist palliative care referral, (b) provision of supportive care, and (c) EOL cancer treatment decisions. Methods. We randomly surveyed 240 oncology specialists at our tertiary care cancer center to assess their attitudes toward EOL care using a score derived from the Jackson et al. qualitative conceptual framework (0 5 uncomfortable and 8 5 highly comfortable with EOL care). We determined the association between this score and clinicians' report of specialist palliative care referral, provision of supportive care, and EOL cancer treatment decisions. Results. Of the 182 respondents (response rate of 76%), the median composite EOL care score was 6 (interquartile range, 5-7). A higher EOL score was significantly associated with solid tumor oncology (median 7 vs. 6 for hematologic oncology; p5.003), a greater willingness to refer patients with newly diagnosed cancer to specialist palliative care (median, 7 vs. 6; p=.01), greater comfort with symptom management (median, 6 vs. 5; p=.01), and provision of counseling (median, 7 vs. 4; p<.001) but not with cancer treatment decisions. We observed a gradient effect, with higher scores associated with a greater proportion of patients referred to palliative care (score 0-4, 27%; 5, 31%; 6, 32%; 7, 35%; and 8, 45%; p=.007). Conclusion. Greater comfort with EOL care was associated with higher rates of specialist palliative care referral and self-reported primary palliative care delivery. More support and education are needed for oncologists who are less comfortable with EOL care.