AbstractLittle is known about patients reporting extremely poor health-related quality of life (HRQoL). This study targeted population with inferior HRQoL and examined their problems experienced with HRQoL dimensions, and impacts of different morbidities on these problems. Data were obtained from a population-based survey in Korea. HRQoL was measured by EQ-5D questionnaire and low-HRQoL population was defined as individuals whose EQ-5D utility score was among the lowest 5% of total survey population. Logistic regression models were used to evaluate the impact of fifteen morbidities on HRQoL dimensions. Of 2976 low-HRQoL participants, females and low socioeconomic individuals were predominant. They experienced significantly more problems in all dimensions, with pain/discomfort, and mobility as the most frequently reported problems. Problems in HRQoL dimensions diverged according to diseases. Individuals with arthritis experienced more difficulties with mobility (aOR 2.62, 95% CI 1.77–3.87) and pain/discomfort (aOR 2.86, 95% CI 1.78–4.60). Stroke patients experienced more problems in self-care (aOR 2.24, 95% CI 1.59–3.15) and usual activities (aOR 1.87, 95% CI 1.11–3.14). Having two or more diseases was associated with worse outcomes in usual activities and increased risk of depression. Thus, efforts to improve status of low-HRQoL should be customized to fulfil unmet needs corresponding to various diseases, and depression prevention is needed for those with multimorbidity status.