ABSTRACT: BACKGROUND:Given the growth in dense breast notification (DBN) legislation in the United States, we examined the association between different types of DBN laws and supplemental screening behaviors among women. METHODS:We surveyed in March-April 2018 a nationally representative sample of women aged 40-59 years who received a routine screening mammogram in the past 18 months. Survey items included the following topics regarding supplemental screening: discussing risks or benefits with a provider, knowledge about the risk of false positives, and utilization. We grouped women by state DBN into non-DBN, generic DBN (mentions breast density but not supplemental screening), DBN that mentions supplemental screening (DBN-SS), and DBN with mandated insurance coverage for supplemental screening (DBN-coverage), and estimated adjusted predicted probabilities for supplemental screening behaviors. RESULTS:Of 1641 women surveyed, 21.3% resided in non-DBN, 41.2% in generic DBN, 25.8% in DBN-SS, and 12.5% in DBN-coverage states. Overall, 23.0% of respondents had discussed supplemental screening with a provider, 11.3% of whom discussed the risks, and 49.5% discussed the benefits. In adjusted analysis, women living in DBN-coverage states were more likely to discuss supplemental screening (27.5%) than women in non-DBN states (13.6%); pairwise contrast 13.8% (95% CI, 2.1% to 25.6%; P = .01). They were also more likely to have received supplemental screening for increased breast density (19.3%) compared to women living in non-DBN (9.9%); contrast 9.4% (95% CI, 1.6% to 17.3%; P = .01), Generic DBN (7.3%); difference 12.0% (95% CI, 4.6% to 19.4%; P =< .001), and DBN-SS (8.8%); contrast 10.5% (95% CI, 2.6% to 18.5%; P < .01) states. CONCLUSIONS:Women in DBN-coverage states were more likely to discuss supplemental screening with their providers, and to undergo supplemental screening, compared to women in states with other types of DBN laws, or without DBN laws.