Sodium bicarbonate (NaHCO3) ingestion has been found to be ergogenic in high-intensity exercise that ranges from 1 to 10min; however, limited studies have investigated high-intensity exercise beyond this duration. The present study aimed to determine the effect of NaHCO3 ingested using a carbohydrate hydrogel delivery system on 40km time trial (TT) performance in trained male cyclists. Fourteen trained male cyclists ingested 0.3gkg-1 BM NaHCO3 (Maurten AB, Sweden) to determine individualised peak alkalosis, which established time of ingestion prior to exercise. Participants completed a 40km familiarisation TT, and two 40km experimental TTs after ingestion of either NaHCO3 or placebo in a randomised, double-blind, crossover design. NaHCO3 supplementation improved performance (mean improvement = 54.14s ± 18.16s; p = 0.002, g = 0.22) and increased blood buffering capacity prior to (HCO3- mean increase = 5.6 ± 0.2mmolL-1, p < 0.001) and throughout exercise (f = 84.82, p < 0.001, pη2 = 0.87) compared to placebo. There were no differences in total gastrointestinal symptoms (GIS) between conditions either pre- (NaHCO3, 22 AU; Placebo, 44 AU; p = 0.088, r = 0.46) or post-exercise (NaHCO3, 76 AU; Placebo, 63 AU; p = 0.606, r = 0.14). The present study suggests that ingesting NaHCO3 mini-tablets in a carbohydrate hydrogel can enhance 40km TT performance in trained male cyclists, with minimal GIS. This ingestion strategy could therefore be considered by cyclists looking for a performance enhancing ergogenic aid.