The present study aimed to examine the effects of repeated low-dose caffeine consumption during a night of total sleep deprivation on psychological state and blood levels of oxidative stress markers after an exhaustive endurance exercise. Twelve recreational runners performed four test sessions in a double-blind randomized order following a baseline night (BN) or a night of total sleep deprivation (TSD). At each test session, blood samples were collected and psychological tests were performed before and after exercise. In comparison with placebo, caffeine ingestion decreased the feeling of sleepiness (FSL) by 28.1% (p < 0.05), reduced the feeling of muscle pain (FMP) by 10.5% (p < 0.05), enhanced the feeling of well-being (FW) by 31.6% (p < 0.05) after TSD, and did not affect levels of oxidative stress markers. Therefore, Caffeine is an effective strategy to counteract psychological adverse effects induced by TSD without being pro-oxidant during endurance exercise. [ABSTRACT FROM AUTHOR]