This review article by Casqueiro, Casqueiro, and Alves discusses the increased susceptibility of patients with diabetes mellitus (DM) to infectious diseases and the mechanisms underlying this increased risk. The authors highlight that DM is associated with immune dysfunction, including reduced neutrophil function, depressed antioxidant systems, and humoral immunity, which collectively contribute to a higher frequency and severity of infections. The review covers a wide range of infections, including respiratory infections, tuberculosis, urinary tract infections, gastrointestinal and liver infections, skin and soft tissue infections, foot infections, and others. It also emphasizes the role of specific pathogens in diabetic patients, such as *Streptococcus pneumoniae*, influenza virus, *Mycobacterium tuberculosis*, and *Candida*. The article recommends immunization with anti-pneumococcal and influenza vaccines to reduce hospitalizations, deaths, and medical expenses associated with these infections. Additionally, the review explores the complex relationship between DM and other infections, such as human immunodeficiency virus (HIV) and hepatitis B and C, and discusses the challenges in managing these infections in diabetic patients. The authors conclude by calling for more research to clarify the immunopathogenic mechanisms linking DM and infections and to improve vaccination coverage for diabetic patients.This review article by Casqueiro, Casqueiro, and Alves discusses the increased susceptibility of patients with diabetes mellitus (DM) to infectious diseases and the mechanisms underlying this increased risk. The authors highlight that DM is associated with immune dysfunction, including reduced neutrophil function, depressed antioxidant systems, and humoral immunity, which collectively contribute to a higher frequency and severity of infections. The review covers a wide range of infections, including respiratory infections, tuberculosis, urinary tract infections, gastrointestinal and liver infections, skin and soft tissue infections, foot infections, and others. It also emphasizes the role of specific pathogens in diabetic patients, such as *Streptococcus pneumoniae*, influenza virus, *Mycobacterium tuberculosis*, and *Candida*. The article recommends immunization with anti-pneumococcal and influenza vaccines to reduce hospitalizations, deaths, and medical expenses associated with these infections. Additionally, the review explores the complex relationship between DM and other infections, such as human immunodeficiency virus (HIV) and hepatitis B and C, and discusses the challenges in managing these infections in diabetic patients. The authors conclude by calling for more research to clarify the immunopathogenic mechanisms linking DM and infections and to improve vaccination coverage for diabetic patients.