Aim: was to assess the effects of Ramadan observance upon repeated sprints and associated inflammatory and oxidative stress responses. Methods: Ten young trained boxers were tested during a control period (C), at the end of the first week (R-1), and during the fourth week of Ramadan observance (R-4). On each occasion, they performed three vertical jumps, 10 x 6 s repeated sprints on a cycle ergometer, followed by three final vertical jumps 1 min after. Surface electrodes measured the EMG activity of the vastus lateralis during jumps performed before and after sprinting. Oxidative stress (malondialdehyde, total antioxidant and catalase), inflammatory markers (C-reactive protein, Interleukin-6 and homocysteine), muscle damage (CPK and LDH) and blood glucose were measured at rest and after completing the exercise protocol. Results: The overall sprint performance was reduced at R-1 compared to C (-6.3 ± 1.2%, p = 0.025), but had recovered by R-4. Jump height decreased after the repeated sprints (p