Artificial airways bypass the physiological mechanism of humidification and filtration of the inspired air, increasing, therefore, the possibilities of copious secretions production. Copious secretions increase the danger for atelektasis and respiratory infections. Moreover, clots can be shaped in the interior of the endotracheal tube or thracheostomy, resulting in increased work of breathing (WOB) and reduced odds of successful extubation. It is also possible to lead progressively to complete obstruction of the endotracheal tube. Thus, the choice of a suitable humidification device during mechanical ventilation is of distinguished importance. There are various types of humidifiers. However, hydroscopic Heat and Moisture Exchangers (HMEs) with filter and Heated Humidifiers (HHs), which provide humidity in form of water vapors, are currently used. When they are used correctly, and not in the cases where they are contraindicated, HMEs’ do not have complications and they decrease the cost of hospitalization as well as the staff workload. HMEs are better choice for short duration of intubation (<96 hours) and during transports. HHs are preferred for patients with persisting hypercapnia, chronic respiratory failure and difficulty in ventilator weaning. HHs should be used for patients with prolonged duration of mechanical ventilation or patients that HMEs are contraindicated for. Neither HMEs nor HHs have been accused for increased incidences of ventilator associated pneumonia (VAP).