Intravenous ketone body infusion can increase erythropoietin (EPO) concentrations, but responses to ketone monoester ingestion post-exercise are currently unknown. The purpose of this study was to assess the effect of ketone monoester ingestion on post-exercise erythropoietin (EPO) concentrations. Nine healthy men completed two trials in a randomized, crossover design (one-week washout). During trials, participants performed a one-hour of cycling (initially alternating between 50% and 90% of maximal aerobic capacity for 2 min each interval, and then 50% and 80%, and 50% and 70% when the higher intensity was unsustainable). Participants ingested 0.8 g·kg-1 sucrose with 0.4 g·kg-1 protein immediately after exercise, and at 1, 2, and 3 hours post-exercise. During the control trial (CONTROL), no further nutrition was provided, whereas on the ketone monoester trial (KETONE), participants also ingested 0.29 g·kg-1 of the ketone monoester (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate immediately post-exercise and at 1 and 2 hours post-exercise. Blood was sampled immediately post-exercise, every 15 min in the first hour, and hourly thereafter for 4 hours. Serum EPO concentrations increased to a greater extent in KETONE than CONTROL (time x condition interaction: p = 0.046). Peak serum EPO concentrations were higher with KETONE (mean ± SD: 9.0 ± 2.3 IU·L-1) compared with CONTROL (7.5 ± 1.5 IU·L-1, p < 0.01). Serum beta-hydroxybutyrate concentrations were also higher, and glucose concentrations lower, with KETONE vs CONTROL (both p < 0.01). In conclusion, ketone monoester ingestion increases post-exercise erythropoietin concentrations, revealing a new avenue for orally ingestible ketone monoesters to potentially alter haemoglobin mass.