Objective It is not fully understood whether and how socioeconomic status (SES) has a prognostic impact in patients with heart failure (HF). We assessed SES and its association with patient characteristics and outcomes in a contemporary and well-characterised HF cohort. Methods Socioeconomic risk factors (SERF) were defined in the Swedish HF Registry based on income (low vs high according to the annual median value), education level (no degree/compulsory school vs university/secondary school) and living arrangement (living alone vs cohabitating). Results Of 44 631 patients, 21% had no, 33% one, 30% two and 16% three SERF. Patient characteristics strongly and independently associated with lower SES were female sex and no specialist referral. Additional independent associations were older age, more severe HF, heavier comorbidity burden, use of diuretics and less use of HF devices. Lower SES was associated with higher risk of HF hospitalisation/mortality, and overall cardiovascular and non-cardiovascular events. These associations persisted after extensive adjustment for patient characteristics, treatments and care. The magnitude of the association increased linearly with the increasing number of coexistent SERF: HR (95% CI) 1.09 (1.05 to 1.13) for one, 1.16 (1.12 to 1.20) for two and 1.22 (1.18 to 1.28) for three SERF (p<0.01). Conclusions In a contemporary and well-characterised HF cohort and after comprehensive adjustment for confounders, lower SES was linked with multiple factors such as less use of HF devices and age, but most strongly with female sex and lack of specialist referral; and associated with greater risk of morbidity/mortality.