The increasing global prevalence of diabetes and cancer presents a critical challenge for healthcare systems, as both conditions are driven by overlapping metabolic, environmental, and lifestyle factors. This chapter situates its discussion within the broader context of noncommunicable disease epidemiology, emphasizing that diabetes and cancer are not isolated disorders but interconnected pathophysiological entities sharing common biological mechanisms. It explores how the rising incidence of type 2 diabetes parallels the global escalation of cancer cases which is an epidemiological convergence largely attributed to obesity, sedentary lifestyles, aging populations, and nutritional transitions toward energy-dense diets. The chapter delineates the molecular, clinical, and societal dimensions of the diabetes–cancer relationship. It discusses the mechanistic underpinnings, including hyperinsulinemia, insulin-like growth factor signaling, chronic inflammation, oxidative stress, and dysregulated glucose metabolism that foster oncogenesis in diabetic milieus. Conversely, it examines how cancer therapies such as chemotherapy, radiotherapy, and corticosteroids aggravate insulin resistance, precipitating or worsening diabetes. The chapter also underscores the unique clinical vulnerabilities of diabetic cancer patients, including heightened toxicity, impaired recovery, and increased recurrence risks. Further, the chapter presents preventive strategies encompassing lifestyle modification, metformin therapy, and evidence-based dietary interventions. It also follows on the transformative role of artificial intelligence, big data, and multi-omics technologies in predicting disease trajectories, identifying biomarkers, and enabling personalized care. The chapter of the book also emphasizes the ethical and public health imperatives, thus addressing healthcare inequities, expanding access to screening and education, and implementing cost-effective interventions, particularly in low- and middle-income countries. Toward the end, this chapter provides a holistic framework for understanding how diabetes and cancer converge at the molecular, clinical, and policy levels. By integrating biomedical evidence with population-level strategies, it advocates a shift from disease-specific management toward a unified, prevention-oriented paradigm capable of reducing the global burden of both disorders and fostering equitable, sustainable health outcomes.