This study evaluated the impact of the ‘Be Cancer Alert’ mass media campaign for breast cancer (BCAC-BC) in terms of changes to women’s health beliefs regarding BC susceptibility and the benefits and barriers of breast cancer screening in Malaysia. Pre- and post-campaign surveys evaluated changes in health beliefs among women aged 40 years and above (n = 676). The perceived susceptibility to breast cancer was significantly higher at follow-up (mean ± SD: 7.30 ± 2.77 vs. 7.63 ± 2.58, p = 0.008) whereas the mean score for the perceived benefits of undertaking screening was high at baseline and follow-up (16.34 ± 2.36 vs. 15.95 ± 2.07, p = 0.001). The perceptions or beliefs about barriers to screening did not change significantly (31.70 ± 8.26 vs. 31.77 ± 7.63, p= 0.841). Regression analyses indicated that mean scores for the barriers subscale were significantly lower among Chinese women (−2.61, 95%CI −4.67, −0.55, p = 0.013) compared to Malay, and among single compared to married women (−2.40, 95%CI −4.60, −0.21, p = 0.032) after adjustment for other demographic variables and past screening history. Malaysian women appeared to already have positive perceptions before the BCAC-BC mass media campaign about the benefits of BC screening. However, the campaign appeared to be linked to both an increased awareness of the susceptibility to breast cancer and to positive beliefs that countered emotional barriers to screening, particularly among single women and Chinese-Malay women.