Abstract Background Not only patients with heart failure (HF), but also their caregivers have reported experiencing distress, depression, anxiety, social isolation, and health problems related to caring for a patient. Needs assessment tools have been used in clinical practice to identify patients' problems and needs from an early stage, however, their relationship with caregiver burden and the severity of the HF patients they care for has not been well investigated. Purpose The purpose of this study is to examine the relationship between distress and HF severity in patients and their caregivers using the Needs Assessment Tool: Progressive Disease-Heart Failure (NAT: PD- HF). Methods We enrolled consecutive 106 chronic HF patients who were admitted to a university hospital and assessed needs by the NAT: PD-HF between February 2023 and July 2023. We also enrolled 95 of their caregivers. The NAT: PD-HF is administered by the health care provider in the form of an interview with the patient and their caregiver. The questionnaire consists of an assessment of the patient's well-being and an assessment of the caregiver's ability to care for the patient. The healthcare provider completes the tool by indicating the level of distress (none, mild, significant) for each section. The severity of the New York Heart Association (NYHA) functional classification is examined in each patient. Results The median age was 72 years (interquartile range 59-81), and 41% were in NYHA class III or IV. The most common relationship between patients and their primary caregivers was partners (53%), followed by children (26%), parents (8%), and siblings (5%). There were 100 patients (94%) with more than mild distress, 57 with NYHA I or II and 43 with NYHA III or IV (P = 0.037). There were also 84 (88%) caregivers with more than mild distress, 47 with NYHA I or II, and 37 with NYHA III or IV of the patients they cared for (P = 0.026). Twenty-four patients (22.6%) were in severe distress, of which 10 were NYHA I or II and 14 were NYHA III or IV (P = 0.044). Among caregivers, 18 (18.9%) were in severe distress, of whom 6 with NYHA I or II and 12 with NYHA III or IV for whom they are caring (P = 0.010). Conclusions Regardless of the severity of HF, caregivers were found to experience distress as similar rate as that in the HF patients they cared for. The proportion of patients and caregivers experiencing distress was found to increase with the severity of HF. It is important to introduce palliative care for HF from the early stage of the disease and to support not only the patient but also the caregivers by using screening tools to identify distress.