PURPOSE: Previous-day recall (PDR) has been suggested as a valid measurement of type, purpose and amount of sedentary behaviors in youth and adults. However, no studies have explored the feasibility and validity of using PDR to estimate sedentary behaviors in various bouts. This study examined the validity of a self-administered PDR in evaluating the total screen-based sedentary behaviors (SSB) and SSB by types and bouts using the activPAL as a criterion measure. METHODS: One hundred young male adults aged 18-35 years volunteered to participate in the validation study. They completed a web-based PDR over 7 consecutive days, in which three categories of SSB (computer work & surf internet, watching TV/video, and play computer games) were recorded to the nearest 15 minutes. Participants wore an activPAL over the 7 days to determine the daily sedentary time and the sedentary time during each 15-min segment. The activPAL-based SSB were calculated based on the start point and endpoint of sedentary behavior from PDR. Total SSB, SSB by type of activities and by duration of bouts were drawn from PDR. Bivariate correlations between PDR- and activPAL-assessed outcomes were conducted. Bland-Altman Plots were performed to determine the agreement between two methods by type of activities and by the duration of bouts. RESULTS: Total SSB assessed by PDR was associated with activPAL-determined sedentary time (r = 0.37). The absolute mean difference between PDR and activPAL was -1.38 h/day (95% confidence interval [CI]: -3.64, 0.88) for total SSB, -1.07 h/day (95% CI: -3.11, 0.96) for computer work & surf internet, -0.20 h/day (95% CI: -1.17, 0.76) for watching TV/video, and -0.15 h/day (95% CI: -0.95, 0.65) for playing computer games. The mean difference between two methods was smaller for sedentary bouts of ≥ 4 h (-0.20 h/day, 95% CI: -0.69, 0.29) than for the sedentary bout shorter than 1 h (-0.42 h/day, 95% CI: -1.42, 0.57). CONCLUSIONS: The online PDR could be used as an easy and valid tool to identify SSB, in particular the type and bouts of SSB in young male adults.