The aim of this study was to investigate the effect of age on peak blood lactate concentration following a maximal incremental treadmill test in male recreational runners. Seventy runners from four age groups, ≤25 years; 26-35 years; 36-45 years; >45 years, performed an incremental treadmill test starting at 8 km·h-1, and increasing by 1 km·h-1 every three minutes until volitional exhaustion. Blood samples were collected at baseline and at the zero, third, fifth and seventh minutes after test to determine lactate concentrations. Peak lactate concentration (LApeak) was defined for each participant as the highest value among the four samples. The lactate concentrations were influenced by the participants’ age (r = -0.47), with LApeak of the younger runners (10.8 ± 2.6 mmol·L) being higher than the values for the older age categories (8.1 ± 3.1, 7.0 ± 1.1 and 6.9 ± 2.8 mmol·L for those 26-35, 36-45 and >45 years, respectively). The LApeak occurred more frequently at the third and fifth minute after the initiation of the test. In conclusion, the lactate concentrations were higher in the younger group (< 25) and reached peak more frequently at the third and fifth minute after the incremental test.