Abstract: Chronic Obstructive Lung Disease (COLD), including asthma and COPD, represents a significant burden in India, contributing to substantial morbidity and mortality. Metered Dose Inhalers (MDIs) are a primary treatment modality for managing respiratory conditions. This study assessed the knowledge and practice related to MDI use among 110 COLD patients across six hospitals in Idukki and Ernakulam districts. A descriptive correlational design was employed, with data collected using structured questionnaires and practice checklists. Results indicated that 68.2% of participants were above 60 years of age, with most residing in rural areas (98.2%) and having primary education (69.1%). Knowledge scores revealed that 59.1% had average knowledge, while 49.1% demonstrated poor practice. A significant positive correlation (r = 0.783, p < 0.01) was observed between knowledge and practice. Key demographic factors such as age, education, and duration of MDI use were significantly associated with knowledge and practice levels. Findings underscore the need for targeted educational interventions to improve MDI usage techniques.