INTRODUCTION: Although the provision of effective assisted ventilation is the most effective intervention in delivery room resuscitation of depressed newborn infants, there is still limited evidence about which is the optimal device to deliver positive pressure ventilation (PPV). OBJECTIVE: To compare the accuracy of pressures and ventilation rate (VR) delivered to a neonatal simulator with three devices: 240 ml and 450 ml self-infating bags (SIB) and a T-piece resuscitator, and to evaluate the variability in terms of providers' experience. MATERIAL AND METHODS: 76 health care providers divided in two groups according to experience were asked to provide positive pressure ventilation to a neonatal simulator through a facial mask or an endotracheal tube with three ventilating devices: a T-piece resuscitator, a 240 ml and a 450 ml self-infating bags. Participants used each combination of device and interface randomly on 2 consecutive occasions. Mean and maximum PIP and respiratory rate were recorded. Statistical analyses were performed using two-factor analysis of variance for repeated measures. RESULT: SIB 240 and 450 were similar in the mean target peak inspiratory pressure (PIP) but both were significantly different (p < 0.001) from T-piece, although all values were close to the target. Mean VR was over the target for all the devices (p < 0.001). The highest difference found was 7 ± 1.7 breaths/minute with the 240 ml bag when compared with the T-piece using a mask. Experienced operators were closer than novice operators to target VR, regardless of the device or interface. CONCLUSION: The accuracy for the devices was comparable in the variables measured regardless operator´s experience. Overall, the T-piece provided lower PIP while both SIB, higher than the target. The VR was over the target for all the devices. Both SIB and novice participants were associated with higher VR. The intraoperator consistency was comparable in the variables measured with all devices.