An increase in muscle carnosine content, following its chronic supplementation, has been shown to im- prove anaerobic performance. In addition, carnosine can affect plasma glucose concentration and insulin response. However, it is not clear whether the acute ingestion of carnosine can have the same effects. Aim of this study was to investigate the acute effects of carnosine ingestion on anaerobic intermittent per- formance and the responses of blood insulin, glucose, bicarbonate and lactate concentrations to exercise. Twelve healthy, young, active participants (BMI 23.5 ± .6, age: 22 ± 2 years) underwent in two separate occasions (double-blind, randomized, crossover design) the running-based anaerobic test (RAST), con- sisting of 6 × 35-m sprints interspersed with 10 s rest after acute (4 hours before the test) ingestion of ei- ther 1 g of L-carnosine and 1 g of β-alanine or placebo. None significant difference was found between the acute ingestion of carnosine and the placebo conditions in terms of running performance (30.0 ± .8 and 29.8 ± .8, p = .302), perceptual response to exercise (RPE), blood lactate, insulin (23.8 ± 13.0 and 19.5 ± 9.0 μU·ml-1, p = .329), blood glucose (109 ± 23 and 104 ± 12 mg·dl-1, p = .969), and blood bicarbonates (16 ± 2 and 16 ± 2 mEq·l-1, p = .277). In conclusion, the acute ingestion of carnosine had no effect on performance, perceptual response to exercise, blood lactate concentration, insulin, glucose, and bicarbonates responses to exercise compared to a placebo treatment. It is not clear whether these results may be attributed to an insufficient dose of carnosine or to a lack of acute effect per sé.