Background and Aims: To analyze the bidirectional associations between smartphone multitasking and anxiety symptoms among college students. Methods: A prospective cohort study was conducted from October 2021 to May 2022. Smartphone multitasking and anxiety symptoms were assessed using the Assessment of Smartphone Multitasking for Adolescents and the Generalized Anxiety Disorder-7 items, respectively. Linear regression models were used to analyze the associations between smartphone multitasking and anxiety symptoms among college students. Autoregressive cross.lagged models (ARCLM) were used to analyze the bidirectional associations between smartphone multitasking and anxiety symptoms among college students. Results: A total of 953 college students were included in this study, 323 (33.9%) of whom were males. The mean age of participants at baseline was 18.89 +- 1.33 years. The rates of depressive symptoms among college students were 28.1% at baseline and 29.0% at 6-month follow-up, respectively. Pearson correlation analysis showed significant positive correlations between all zero-level variables (p < 0.01). Linear regression analyses showed that after adjusting for demographic characteristics and health risk behaviors, smartphone multitasking was still positively correlated to anxiety symptoms at baseline (ß 5 1.30, 95%CI: 0.54-2.05) and 6-month follow-up (ß 5 0.84, 95%CI: 0.32-1.37). The results of ARCLM showed that smartphone multitasking at baseline was positively correlated with anxiety symptoms after 6-month (ß 5 0.03, p < 0.01), but anxiety symptoms at baseline did not significantly correlate to smartphone multitasking after 6-month among college students (ß 5 0.04, p 5 0.51). Discussion and Conclusions: Smartphone multitasking is associated with higher anxiety symptoms at baseline and followup, but no bidirectional relationship exists. Reducing smartphone use may improve mental wellbeing.  Kulcsszavak: anxiety, college students, cohort study, media multitasking, smartphone, mobile phone addiction