Objective: The aim of this study was to compare the prevalence of heart failure (HF) in relation to age, multimorbidity and socioeconomic status of primary healthcare centres in southern Sweden., Design: A cross-sectional study., Setting: The data were collected concerning diagnoses at each consultation in all primary healthcare centres and secondary healthcare in the southernmost county of Sweden at the end of 2015., Participants: The individuals living in southern Sweden in 2015 aged 20 years and older. The study population of 981 383 inhabitants was divided into different categories including HF, multimorbidity, different levels of multimorbidity and into 10 CNI (Care Need Index) groups depending on the socioeconomic status of their listed primary healthcare centre., Outcomes: Prevalence of HF was presented according to age, multimorbidity level and socioeconomic status. Logistic regression was used to further analyse the associations between HF, age, multimorbidity level and socioeconomic status in more complex models., Results: The total prevalence of HF in the study population was 2.06%. The prevalence of HF increased with advancing age and the multimorbidity level. 99.07% of the patients with HF fulfilled the criteria for multimorbidity. The total prevalence of HF among the multimorbid patients was only 5.30%. HF had a strong correlation with the socioeconomic status of the primary healthcare centres with the most significant disparity between 40 and 80 years of age: the prevalence of HF in primary healthcare centres with the most deprived CNI percentile was approximately twice as high as in the most affluent CNI percentile., Conclusion: The patients with HF were strongly associated with having multimorbidity. HF patients was a small group of the multimorbid population associated with socioeconomic deprivation that challenges efficient preventive strategies and health policies., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)