PURPOSE The aim of the current study was to increase the uptake of screening mammography among high-risk women who were treated for a childhood cancer with chest radiotherapy. PATIENTS AND METHODS Two hundred four female survivors in the Childhood Cancer Survivor Study who were treated with chest radiotherapy with 20 Gy or greater, age 25 to 50 years, and without breast imaging in the past 24 months were randomly assigned 2:1 to receive a mailed informational packet followed by a tailored telephone-delivered brief motivational interview (intervention) versus an attention control. Primary outcome was the difference in the proportion of participants who completed a screening mammogram by 12 months as evaluated in an intent-to-treat analysis. Stratum-adjusted relative risk (RR) and 95% CI were estimated using the Cochran-Mantel-Haenszel method. Secondary outcomes included the completion of screening breast magnetic resonance imaging (MRI) and barriers to screening and moderating factors. RESULTS Women in the intervention group were significantly more likely than those in the control group to report a mammogram (45 [33.1%] of 136 v 12 [17.6%] of 68; RR, 1.9; 95% CI, 1.1 to 3.3). The intervention was more successful among women age 25 to 39 years (RR, 2.2; 95% CI, 1.1 to 4.7) than among those age 40 to 50 years (RR, 1.4; 95% CI, 0.6 to 3.2). The proportion of women who reported a breast MRI at 12 months was similar between the two groups: 16.2% (intervention) compared with 13.2% (control; RR, 1.2; 95% CI, 0.6 to 2.5). Primary barriers to completing a screening mammogram and/or breast MRI included lack of physician recommendation, deferred action by survivor, cost, and absence of symptoms. CONCLUSION Use of mailed materials followed by telephone-delivered counseling increased mammography screening rates in survivors at high risk for breast cancer; however, this approach did not increase the rate of breast MRI. Cost of imaging and physician recommendation were important barriers that should be addressed in future studies.