Spacers offer a multitude of benefits by reducing the requirement to coordinate inhalation with actuation and improving inhaler technique in patients using a pressurized metered dose inhaler (pMDI). Spacers improve drug targeting by retaining within the spacer large particles normally deposited in the oropharynx, and by creating a prolonged aerosol cloud of fine particles to give the user increased time to inhale after actuation. This is particularly important in young children and the elderly to effectively deliver medication to the airways. Areas covered: By investigating the history and features of spacers, we demonstrate that the advantages of using spacers far outweigh their limitations. We also discuss the optimal characteristics of spacers in terms of shape, volume, presence of valve and static charge, and present a detailed discussion of the VENTOLIN™ Mini Spacer. Expert opinion: Generally, the shape and size of spacers makes them inherently inconvenient. Consideration of human factors and modern design may make them more attractive to patients. However, the incentive to use spacers should be their ability to help patients correctly use inhaled medications delivered by pMDIs. Understanding of these principles through education is key to their acceptance by patients.