The advent of inhaled corticosteroids (ICS) brought a revolution in the management of asthma, representing now the cornerstone in this pathological condition treatment. Indeed, these drugs have clearly shown to possess a high degree of both efficacy and safety. Beclomethasone dipropionate (BDP) is the first molecule tested in the early 1970s. When administered via nebulizers or pressurized metered-dose inhalers (pMDI), BDP was found to be effective in reducing the symptoms frequency and severity in asthmatic patients, even in those previously treated with low-dose oral corticosteroids. The drug was thus produced to be administered by nebulization or via pMDI. Nebulizers are a practical and efficient tool for administering inhaled drugs in patients of all degree of severity and belonging to all ages, but are especially useful for those unable to utilize other inhaler devices correctly. BDP aerosolization, when generated by modern pneumatic nebulizers, can deliver particles with a mass median aerodynamic diameter (MMAD) value of 2.9-3.7 µm. This ability allows the deposition of the drug in small caliber airways, and considerably reduces the amount of drug deposited in the oropharynx, thus improving this molecule pharmacokinetics. This review aims to analyze the factors influencing the efficacy and safety of ICS, evaluating in detail the characteristics of BDP administered by nebulization.