The Dietary Approaches to Stop Hypertension (DASH) dietary pattern has been associated with a lower risk of incident heart failure (HF); however, previous studies were conducted in mostly middle-income White populations. The association between DASH and incident HF risk in lower income and Black individuals is less well understood. We analyzed 25,300 White and Black adults without a history of HF at enrollment (2002 to 2009) in the Southern Community Cohort Study receiving Centers for Medicare and Medicaid Services. Alignment with DASH was assessed at enrollment using a validated food frequency questionnaire. Incident HF was ascertained from Centers for Medicare and Medicaid Services claims through 2016. The association between DASH diet alignment and incident HF was examined in multivariable-adjusted Cox proportional hazards regression models, including an interaction term testing effect modification by income. The cohort was predominantly middle-aged (median 54 years), Black (68%), female (63%), and low-income (88% <$25,000/year/household). Socioeconomic factors, including education and annual income, were larger contributors to the variance in DASH score than were cardiovascular co-morbidities. The association between DASH dietary alignment and HF risk was not significant overall (hazard ratio [HR] 1.00; 95% confidence interval [CI] 0.96 to 1.04) or in race-sex groups. However, the association between alignment with the DASH diet and HF risk significantly varied by income (interaction p = 0.030), with neutral and inverse associations in lower (<$25,000/year) and higher ($≥25,000) income participants, respectively. In conclusion, income modified the association between healthier dietary patterns and risk of incident HF. In lower income participants, greater alignment with the DASH diet was not associated with lower HF risk.