https://www.selleckchem.com/products/AM-1241.html 3 min/wk vs. objectively-measured 1,170.7 min/wk, p<0.001). Most of the over-reporting was contributed by the web browsing domain (self-reported 447.8 min/wk vs. objectively-measured 33.3 min/wk, p<0.001). Our results showed large discrepancies between self-reported smartphone and objectively-measured smartphone usage except for self-reported usage on game apps. Our results showed large discrepancies between self-reported smartphone and objectively-measured smartphone usage except for self-reported usage on game apps. As smartphone use is becoming more common, the age of initial exposure to devices is becoming younger. Young children's screen use is influenced by various factors; it is more directly dependent on family environment than school-aged children. Our study aimed to examine the effect of mother's smartphone addition on their child's smartphone use. Participants were from the Kids Cohort for Understanding of internet addiction Risk factors in early childhood (K-CURE) study. Adult smartphone addiction self-diagnosis scale was used to evaluate smartphone addiction degree of mother. Child's smartphone use was assessed by parental questionnaire. Using logistic regression analysis, we examine the association between mother's smartphone addiction and child's smartphone use. After adjusting for other factors, mother's smartphone addiction is related with early smartphone exposure of children. Highrisk group's children was exposed to smartphone earlier than low risk group (adjusted OR, 0.418; p=0.021). Contrary to expectation, there is no correlation between mother's smartphone addiction and child's smartphone use time. Our study explain that mother's smartphone addiction can affect early smartphone exposure on children. Based on our findings, further study might explore the effect of early smartphone exposure on children. Our study explain that mother's smartphone addiction can affect early smartphone exposure on c