Dietary protein ingestion following exercise increases muscle protein synthesis rates, stimulates net muscle protein accretion, and facilitates the skeletal muscle adaptive response to prolonged exercise training. Furthermore, recent studies show that protein ingestion before and during exercise also increases muscle protein synthesis rates during resistance- and endurance-type exercise. Therefore, protein ingestion before and during prolonged exercise may represent an effective dietary strategy to enhance the skeletal muscle adaptive response to each exercise session by extending the window of opportunity during which the muscle protein synthetic response is facilitated. Protein ingestion during exercise has also been suggested to improve performance capacity acutely. However, recent studies investigating the impact of protein ingestion during exercise on time trial performance, as opposed to time to exhaustion, do not report ergogenic benefits of protein ingestion. Therefore, it is concluded that protein ingestion with carbohydrate during exercise does not further improve exercise performance when compared with the ingestion of ample amounts of carbohydrate only.