- Objective To further validate the use of the Modified Tal Score (MTS), a clinical tool for assessing bronchiolitis severity, by physicians with varying experience and training levels, and to determine the ability of the MTS to predict bronchiolitis severity. Methods This prospective cohort study included infants of <12 months of age who were diagnosed with bronchiolitis and assessed via MTS. We calculated the intra‐class correlation coefficient (ICC) among four groups of raters: group 1, board‐certified pediatric pulmonologists; group 2, board‐certified pediatricians; group 3, senior pediatric residents; and group 4, junior pediatric residents. Clinical outcomes were determined as length of oxygen support and length of stay (LOS). We assessed MTS's prediction of these outcomes. Relative risk (RR) for clinical severity was calculated via a Generalized Linear Model. Results Twenty‐four physicians recorded a total of 600 scores for 50 infants (average age 5 ± 3 months; 56% male). The ICC values with group 1 as a reference were 0.92, 0.87, and 0.83, for groups 2, 3, and 4, respectively (P < 0.001). RR for oxygen support required was; 1.33 (CI 1.12‐1.57), 1.26 (1.1‐1.46), 1.26 (1.06‐1.5), and 1.21 (0.93‐1.58) for groups 1, 2, 3, and 4, respectively. RR for LOS was; 1.15 (CI 0.97‐1.37), 1.19 (1.03‐1.38), 1.18 (1.0‐1.39), and 1.18 (0.93‐1.51) for groups 1, 2, 3, and 4, respectively. Conclusion The MTS is a simple and valid scoring system for evaluating infants with acute bronchiolitis, among different physician groups. The first score upon admission is a fair predictor of oxygen requirement at 48 h, and LOS at 72 h.