ImportanceSome drugs are heavily marketed through direct-to-consumer advertising.ObjectiveTo identify drug characteristics associated with a greater share of promotional spending on advertising directly to consumers.Design, Setting, and ParticipantsExploratory cross-sectional analysis of drug characteristics and promotional spending for the 150 top-selling branded prescription drugs in the US in 2020 as identified from IQVIA National Sales Perspectives data. Promotional spending data were provided by IQVIA ChannelDynamics.ExposuresDrug characteristics (total 2020 sales; total 2020 promotional spending; clinical benefit ratings; number of indications, off-label use; molecule type; nature of condition treated; administration type; generic availability; US Food and Drug Administration [FDA] approval year, World Health Organization anatomical therapeutic chemical classification; Medicare annual mean spending per beneficiary; percent sales attributable to the drug; market size; market competitiveness) assessed from health technology assessment agencies (France’s Haute Autorité de Santé and Canada’s Patented Medicine Prices Review Board) and drug data sources (Drugs@FDA, the FDA Purple Book, Lexicomp, Merative Marketscan Research Databases, and Medicare Spending by Drug data).Main Outcomes and MeasuresProportion of total promotional spending allocated to direct-to-consumer-advertising for each drug.ResultsThe 2020 median proportion of promotional spending allocated to direct-to-consumer advertising was 13.5% (IQR, 1.96%-36.6%); median promotional spending, $20.9 million (IQR, $2.72-$131 million); and median total sales, $1.51 billion (IQR, $0.97-$2.26 billion). Of the 150 best-selling drugs, 16 were missing data and key covariates; therefore, the primary study sample comprised 134 drugs. After adjustment for multiple drug characteristics, the mean proportion of total promotional spending allocated to direct-to-consumer advertising for the remaining 134 drugs was an absolute 14.3% (95% CI, 1.43%-27.2%; P = .03) higher for those with low added clinical benefit than for those with high added clinical benefit and an absolute 1.5% (95% CI, 0.44%-2.56%; P = .005) higher for each 10% increase in total sales.Conclusions and RelevanceAmong top-selling US drugs in 2020, a rating of lower added benefit and higher total drug sales were associated with a higher proportion of manufacturer total promotional spending allocated to direct-to-consumer advertising. Further research is needed to understand the implications of these findings.