OBJECTIVETo assess the respective value of Traditional clinical rotation and High Fidelity Simulation (HFS) on the acquisition of clinical reasoning (CR) skills in Medical Students. METHODSA randomized controlled trial was conducted. Forty medical students were exposed to a full day of HFS, either during their Paediatric Term (PT) (Experimental group = PT+, HFS+) or, after completion of their PT (Control group = PT+, HFS-). CR skills were assessed by a Script Concordance Test (SCT) prior to group allocation and at the completion of PT. RESULTS39 out of 40 students completed both SCT. Scores before (mean/SD 57.4/6.7) and after (mean/SD 61.1/7.0) the PT were significantly improved (mean increase [95% confidence interval (CI)]: 3.6 [2.0-5.2]; p<0.0001; n=39). There was no added improvement from involvement in a full day of HFS in SCT scores between the experimental and the control groups (mean increase [95% CI]: 3.2 [0.5-5.9], n=18 versus 4.0 [1.9-6.1], n=21, respectively; p=0.61).