Abstract Muco-obstructive airway diseases (MADs) are chronic, life-threatening conditions that cause more than 3 million annual deaths worldwide. MADs are characterized by excess mucus accumulation in the airways, inflammation, chronic infection, and progressive respiratory failure. Pseudomonas aeruginosa (Pa) is the primary bacterial pathogen associated with MADs infections. Pa colonization leads to declining lung function, reduced quality of life, and decreased life expectancy in people with MADs. Diabetes is a frequent comorbidity affecting 18-50% of individuals with underlying MADs. Diabetes is associated with worse MADs clinical outcomes and increased susceptibility to severe pulmonary infections. In addition, diabetes is associated with increased antibiotic treatment failure in individuals with MADs. Utilizing novel in vitro and in vivo model systems, we have observed increased virulence potential and higher tolerance to antibiotic treatments in Pa under diabetic MADs-like conditions. These observations raise several questions such as how the diabetic microenvironment in MADs induces Pa virulence and how it leads to higher rates of antibiotic tolerance. We hypothesize that diabetic hyperglycemia in the lung microenvironment enhances bacterial fitness and potentiates bacterial virulence. We further hypothesize that hyperglycemia alters bacterial metabolism towards increased tolerance to antibiotic therapies. We will address these questions in both in vitro systems that reflect the MADs and diabetes lung environment and in a diabetic murine chronic infection model of MADs. This proposal will address key research areas including the influence of diabetes comorbidities in Pa virulence and antibiotic treatment failure in MADs.