Introduction Primary hyperparathyroidism is strongly associated with cardiovascular disease. It is related to hypertension, left ventricular hypertrophy, cardiac valvular abnormalities, arrhythmias, and heart failure. While primary hyperparathyroidism can lead to ventricular stiffness, coronary artery and valvular calcifications, we aim to investigate the effects of primary hyperparathyroidism on mortality and length of hospital stay in patients admitted for acute congestive heart failure exacerbation. Methods National Inpatient Sample (NIS) database from years 2007-14 was examined for all hospital admissions with HF with and without hyperparathyroidism. Baseline characteristics were compared using parametric and non-parametric tests for continuous variables and Chi-Squares. Multivariate logistic regression was used to draw comparisons between incidence of cardiogenic shock, in-hospital mortality and length of stay (LOS). Our analysis was adjusted for age, sex, race, payer, income quartiles, hospital location, region, size and teaching status and included multiple comorbidities. Results A total of 7,000,805 patients were admitted for CHF exacerbation and of those 21,765 (0.31%) also had hyperparathyroidism. Mean age for hyperparathyroid patients was 72.0 years vs. 72.8 yrs (p Conclusion Overall, while our results showed that patients with hyperparathyroidism admitted for CHF exacerbation had a decreased in-hospital mortality, they had more comorbidities and tended to stay in the hospital longer. While in-hospital mortality could be multifactorial, a longer LOS can possibly be due to the underlying physiological changes that PTH and calcium levels have on the heart, including increased LV stiffness and LV hypertrophy, lengthening the time to euvolemia.