The current cross-sectional study aimed to investigate eHealth literacy among adult workers in China and explore the relationship between eHealth literacy and mental health in this population. Convenience sampling was used to conduct a survey among adult workers aged 18 to 60 years. Potential participants were chosen from those who completed physical examinations at the Health Management Center of one hospital in China. Participants' eHealth literacy and mental health were assessed using the eHealth Literacy Scale, Patient Health Questionnaire, Generalized Anxiety Disorder Scale, and Perceived Stress Scale. Mean scores for eHealth literacy and perceived stress were 28.39 (SD = 5.78) and 5.49 (SD = 2.61), respectively. Depression and anxiety were found in 8.2% and 10.1% of participants, respectively. Multivariate logistic regression analysis showed that a 1-point increase in eHealth literacy score was associated with a 7% decrease in depressive symptoms (odds ratio [OR] = 0.93, 95% confidence interval [CI] [0.88, 0.99]) and a 6% decrease in anxiety symptoms (OR = 0.94, 95% CI [0.89, 0.99]). Furthermore, multiple linear regression analysis showed that perceived stress decreased 0.08 points (B = -0.08, 95% CI [-0.13, -0.04]) with every 1-point increase in eHealth literacy score. Thus, eHealth literacy has the potential to reduce risk of depression, anxiety, and perceived stress, and to promote the mental health of adult workers. [Journal of Psychosocial Nursing and Mental Health Services, 61(9), 40-46.].