Background With advancing illness, some patients with heart failure (HF) opt to receive life-extending treatments despite their high costs, while others choose to forgo these treatments, emphasizing cost containment. We examined the association between patients’ health status and their preferences for treatment cost containment versus life extension and whether their patients’ awareness of disease incurability moderated this association. Methods In a prospective cohort of patients ( N = 231) with advanced HF in Singapore, we assessed patients’ awareness of disease incurability, health status, and treatment preferences every 4 mo for up to 4 y (up to 13 surveys). Using random effects multinomial logistic regression models, we assessed whether patients’ awareness of disease incurability moderated the association between their health status and treatment preferences. Results About half of the patients in our study lacked awareness of HF’s incurability. Results from regression analyses showed that patients with better health status, as indicated by lower distress scores (odds ratio [OR] [95% confidence interval {CI}]: 0.862 [0.754, 0.985]) and greater physical well-being (1.12 [1.03, 1.21]); and who lacked awareness of their disease’s incurability were more likely to prefer higher cost containment/minimal life extension treatments compared with lower cost containment/maximal life extension. Conclusions This study underscores the significance of patients’ awareness in disease incurability in shaping the relationship between their health status and treatment preferences. Our findings emphasize the need to incorporate illness education during goals-of-care conversations with patients and the importance of revisiting these conversations frequently to accommodate changing treatment preferences. Highlights The health status of patients with advanced heart failure was associated with their treatment preferences. Patients whose health status improved and who lacked awareness of their disease’s incurability were more likely to prefer higher cost containment/minimal life extension treatments.