PurposeTo evaluate knowledge of secondhand smoke (SHS) risks, sources of information, and associated factors and behaviors among hospital staff.MethodsWe conducted a cross-sectional survey using a 40-item self-administered questionnaire among 328 employees at a university hospital. The questions on representative diseases related to SHS were used to measure the degree of knowledge of SHS. Multiple regression analysis was used to determine the correlation between SHS knowledge scores and variables.ResultsFemales had better SHS knowledge scores than males, regardless of smoking status (p<0.05). SHS knowledge was positively correlated with cessation education in males, non-smokers, and the total sample (β = 3.950, 2.356, and 2.684, respectively, p<0.05). It was correlated with the experience of any SHS exposure-related symptoms in males, non-smokers, and the total sample (β = 3.950, 2.356, and 2.684, respectively, p<0.05) and discomfort when exposed to SHS in non-smokers and the total sample (β = 0.670 and 0.821, respectively, p<0.05).ConclusionSHS knowledge is high among females, when hospital staff are educated about SHS risks, and when they have experienced any SHS exposure-related symptoms or felt uncomfortable when exposed to SHS. SHS risk education is an effective tool to increase SHS knowledge in hospital staff.