The increasing population of patients with chronic diseases generates great challenge of chronic disease management. The occurrence of mobile health monitoring service is beneficial to chronic disease prevention and health promotion. The objective of this study is to investigate how the patients with chronic diseases make usage decisions on mobile health monitoring service. A survey comprising 261 subjects were conducted to validate the research model and proposed hypotheses. The results revealed that health severity positively influences mobile health monitoring service use intention, while negative health emotions do not. Health uncertainty avoidance strengthens the effect of health severity but weakens the effect of negative health emotions on mobile health monitoring service use intention. Limitations and implications for research and practice are discussed.