Despite health benefts reported recently, 2′-fucosyllactose (2′-FL) concentration in maternal milk was not conclusively reported because it varies between countries and mothers. Particularly, its distribution among Korean mothers was not obtained from a reliable sample group yet. Thus, a dynamic range for 2′-FL concentration in Korean mothers’ milk was investigated from 102 samples. A quantitative method using multiple reaction monitoring (MRM) by triple-quadrupole-mass spectrometry has been evaluated by a standard procedure of method validation. The 2′-FL concentration was in the range of 0.4 to 2.6 g/L overall. While the samples from secretor mothers (n=80) contained 1.0 to 2.8 g/L of 2′-FL, the maternal milk from non-secretor mothers (n=22) had 0.01 to 0.06 g/L of 2′-FL only. In addition to the genetic variation of mothers, the lactation period impacted the 2′-FL concentration. The average 2′-FL concentration of the late-stage group (>60 days) was 78% of that obtained from the frst month of postpartum mothers.