Inefficient inhaler technique is a common problem resulting in poor drug delivery, decreased disease control and increased inhaler use. The aim of this study was to assess patients' use of different inhaler devices and to ascertain whether patient preference is indicative of ease of use and whether current inhaler use has any influence on either technique or preference. We also wished to define the most appropriate method of selecting an inhaler for a patient, taking into account observed technique and device cost. One hundred patients received instruction, in randomized order, in the use of seven different inhaler devices. After instruction they were graded (using predetermined criteria) in their inhaler technique. After assessment patients were asked which three inhalers they most preferred and which, if any, they currently used. Technique was best using the breath-actuated inhalers; the Easi-Breathe and Autohaler, with 91% seen to have good technique. The pressurized metered dose inhaler (pMDI) fared poorly, in last position with only 79% of patients showing good technique, despite being the most commonly prescribed. The Easi-Breathe was by far the most popular device with the patients. The Autohaler came in second position closely followed by the Clickhaler and Accuhaler. The majority of patients (55%) currently used the pMDI but the pMDI did not score highly for preference or achieve better grades than the other devices. Only 79% of patients tested could use the pMDI effectively even after expert instruction yet it continues to be commonly prescribed. This has important repercussions for drug delivery and hence disease control. Prescribing a patient's preferred device increases cost but can improve efficiency and therefore be cost effective in the long term. Using an inexpensive device (pMDI) when technique is good and the patient's preferred inhaler device when not is one way to optimize delivery and may even reduce cost.