The present study examined the ergogenic effects of seven days of New Zealand blackcurrant (NZBC)BC extract on 2000-meter rowing ergometer performance and cognitive function. Using a double-blind, placebo-controlled crossover-study design, 9 trained male rowers from Iran's national team were recruited to participate in three sessions with NZBC extract (600 mg∙day−1), placebo (PL) and control (CL) treatments for 7 days with a 14 days washout period. Participants completed a 2000-meter ergometer performance, rating of perceived exertion (RPE) immediately, and cognitive function test was measured five minutes after the rowing test. The results revealed that 7 days of NZBC extract supplementation despite showing a small effect size (Cohens d=0.23) with the smallest worthwhile change to be 2.96 s, had no statistical ergogenic effects (420 ± 12 s, 95%CI [411, 430] compared to PL (424 ± 15 s, 95%CI [412, 435] and CL (423 ± 14s, 95%CI [412, 434 s] in rowing performance. Notably, 6 of the 9 participants exhibited an non-significant enhancement in rowing performance with NZBC extract. For other parameters, there were no differences between the NZBC extract, PL, and CL conditions (p > 0.05). Seven days of NZBC extract supplementation did not improve rowing performance, cognitive function, or RPE among national team rowers.