Ventilations during Basic Life Support (BLS) should be done quickly to achieve short interruptions of the chest compression (CC). In this setting, bag-mask ventilation (BMV) is standard, but requires much training. We investigated the influence of the laryngeal tube (LT) on the "no-flow time" (NFT) and quality of ventilation during BLS compared to the BMV on manikins in a 1- and 2-rescuermodel. The probands were trained in BMV, but inexperienced in the use of LT. In the 1-rescuer-model a shorter NFT could be achieved by the use of LT, but in the 2-rescuer-model it led to an extension. With regard to the quality of ventilation, the LT was superior to BMV in both models. In the 1-rescuer-model, the proband had a fixed ventilation option using the LT. Though, change of position from CC to ventilation was quick. With BMV, the proband was forced to change position and place the mask on the manikin for each ventilation. These handles are time-consuming. In the 2-rescuer-model, there was no change of positions necessary. Though, NFT was not shortened by the LT but was even prolonged by administration of larger tidal volumes.