Illness uncertainty is prevalent in patients awaiting liver transplant. We described high levels of illness uncertainty in these patients and examined relationships between uncertainty and person factors and the antecedents of uncertainty. Mishel uncertainty in illness scale was used to measure illness uncertainty. We used modes and interquartile range (IQR) to describe illness uncertainty levels in 115 patients. Multiple logistic and linear regression models estimated the associations of uncertainty with hypothesized antecedents. High total illness uncertainty score was reported by 15.6% of the patients. After adjusting for all variables, illness uncertainty was associated with two antecedents of uncertainty, low social well-being (OR = 0.816; p  = .025) and low self-efficacy (OR = 0.931; p  = .013). Complexity was negatively associated with social well-being; ambiguity and inconsistency were negatively associated with self-efficacy. One in seven patients experienced high illness uncertainty. Social well-being and self-efficacy were negatively related to illness uncertainty.