1528 Background: Cancer screening for colon, breast, and prostate cancer remains underutilized. Physician (MD)-patient discussions of screening are common but the impact of these discussions is unknown. Methods: 2489 40–70 year old subjects completed a national survey of cancer prevention information acquisition and decision making (median age 53, 49% male, 77% white, 59% married, 61% some college). Subjects reported whether their MD initiated discussions (MDID) about colonoscopy, mammography, & PSA within the past year. Age eligible subjects were “non-routine screeners” (NRS: never screened or colonoscopy >10 yrs, mammography >2 yrs or PSA>2 yrs prior) or “routine screeners” (RS).The endpoint was intention to screen when next eligible. Results: 46%, 75% and 60% of subjects reported intentions to obtain colonoscopy, mammography and/or PSA. Logistic regression was used to determine the association between MDID and intentions to screen controlling for sociodemographics and recency of screening. For colonoscopy and mammography, MDID was significantly associated with intention to screen for NRS but not RS groups; the opposite was true for PSA. For the NRS group: comparing those saying no versus yes to MDID, intentions were 15% vs. 43% for colonoscopy, 29% to 61% for mammography (RS: 85% vs. 91% and 82% vs. 85%). For PSA, NRS: 46% vs.52% but RS group 65% vs. 85%. All interactions (screening by MDID) were significant, p<.001. Conclusions: Given high intentions to undergo colon and breast cancer screening among patients who have been screened routinely, physician discussion preferentially increases intentions for colon and breast cancer screening among patients who are not routinely undergoing the screening test. Conversely, physician discussion preferentially influences prostate cancer screening intentions among patients who have been screened in the past two years- perhaps because men who have not undergone screening are more resolved in their decision not to screen. These results define subgroups of patients where physician attention may have the greatest impact on screening adherence. No significant financial relationships to disclose.