Purpose: To determine (1) Canadian oncologists’ attitudes toward practice guidelines, (2) oncologists’ self-reported use of practice guidelines and, (3) physicians’ characteristics and attitudes associated with self-reported use of practice guidelines. Participants and Methods: A cross-sectional, self-administered postal survey was administered to Canadian oncologists. Main outcome measures were level of agreement with 8 descriptive statements about guidelines, score on the attitudinal scale of the guideline of Tunis et al., and physicians’ stated use of guideline. χ² and logistic regression procedures were used to explore the relationship between physician characteristics and use of guidelines. Results: Over 80% of respondents agreed that they were good educational tools, convenient sources of advice, intended to improve quality of care; over 40% agreed that they were unbiased syntheses of expert opinion. Conversely, 42, 26, 20 and 16% felt they were intended to cut costs, were oversimplified cookbook medicine, were too rigid to apply to individual patients, and a challenge to physicians’ authority, respectively. Forty-one percent reported using practice guidelines routinely or most of the time. Use was associated with positive attitudes about guidelines, receiving medical school training abroad and being a radiation oncologist. Conclusion: Canadian oncologists were quite positive about practice guidelines and reported using them frequently. Our results suggest that use of guidelines by oncologists may be related to attitudes about guidelines in general, specialty within oncology and country of medical school training.