Progressive, permanent structural damage occurs in plain concrete when subjected to time fluctuating stresses and strains. This fatigue process has been under investigation since about the early twentieth century. Investigations of repeated loads, static loads, fracture mechanics, effect of time rate of applied stress, range of applied load, effect of rest period, mechanisms of fatigue failure and damage model etc are discussed briefly in this book. Cycle counting algorithm as well as S-N curve approach is used to estimate the fatigue life. A study on load sequencing effect is provided, numerical simulations shows that the transition from low to high stress levels are more damaging than transitions from high to low stress levels. The present state and limitation of the knowledge in this field are discussed along with the areas for potentially fruitful research.