Proper use of inhaler devices is an essential determinant of asthma or chronic obstructive pulmonary disease (COPD) control and life quality. This cross–sectional study was conducted between October 2017 to January 2018, to evaluate the inhalation technique of asthmatic or COPD patients attending the pulmonary clinic, at King Abdulaziz Hospital in Al Ahsa city. The data was collected using a structured questionnaire to determine the prevalence of proper using of inhalation techniques and to investigate patients‘ characteristics and factors associated with improper use of inhaler devices as well as their relationships with disease control. Of the study population, 37% of the patients used inhalators correctly. The prevalence in females and those 55 years old and asthmatic patients was 59.0%, 54.0%, and 83.0%; respectively. The elderly and patients with a low education level were significantly more likely to make an error performing the technique. Only a third of patients had controlled asthma. This study found the majority of patients use their inhalers incorrectly