The goal of poultry operations is to efficiently convert feed into food, making disease management a critical component of the production process. Over time, avian disease management has shifted from addressing acute diseases in individual animals to managing both clinical and subclinical disease in populations. Morbidity and mortality are no longer the sole metrics monitored; the emphasis has shifted to overall economic performance, product quality, and animal welfare. In this course, we will explore the fundamentals of avian disease prevention, diagnosis, and control. We will discuss the importance of biosecurity, vaccination programs, and proper diagnostic techniques to detect and manage diseases effectively. Through case studies and practical examples, we will develop a comprehensive understanding of how to minimize the impact of diseases on poultry production, ensuring successful outcomes in terms of animal health, welfare, and product quality.