Purpose <p>The aim of the study is to evaluate the effects of pollution on the prevalence of obesity, diabetic complications, and olfactory disfunction – OD (and their relationships) in two comparable groups of patients with type 2 diabetes (T2DM) living in different areas with different exposure to pollutants.</p> Methods <p>Two comparable groups of patients with T2DM coming from the 2 areas in the Lombardy region with the higher (Milan) and the lower (Sondrio) level of pollution in the past 10 years were analyzed. Each patient underwent a diabetologic, ophthalmologic, cardiologic and otorhinolaryngologic examination which also included the assessment of olfactory abilities and olfactory-related quality of life (QoL). Statistical analysis used non-parametric tests and logistic regression.</p> Results <p>The prevalence of diabetic complications and OD was significantly higher in patients from Milan than from Sondrio (<i>p</i> = 0.007 and <i>p</i> = 0.039 at Fisher test, respectively), while no significant difference was found for obesity (<i>p</i> = 0.716 at Fisher test). The group with a greater prevalence of OD also reported worse olfactory-related QoL (<i>p</i> = 0.001 and <i>p</i> = 0.016 at Fishertest respectively for Biref-IT-QOD-P and Biref-IT-QOD-NS, respectively). Regression analysis showed a significant association between OD and the presence of diabetic complications (<i>p</i> = 0.011 at multivariable analysis), and between complications and diabetes duration (<i>p</i> = 0.001 at multivariable analysis). Pollution exposure was a weak independent predictor for both OD and complications in patients with T2DM.</p> Conclusion <p>Our study showed that patients with T2DM subject to a higher exposure to pollution were more frequently affected by diabetic complications and OD and reported a poorer olfactory-related QoL compared to patients with a lower exposure. We were also able to highlight a strong association between OD and T2DM complications.</p>