We studied the capability of pristine, Al-doped and B(OH)2-functionalized graphene nanoflakes for delivery of Letrozole (LT) anticancer agent using density functional theory calculations. It was shown that LT/pristine graphene complex includes very weak physical interaction with Ead = -2.447 kcal.mol-1 which is so weak to be applied in drug delivery purposes. So, graphene nanoflake was doped by Al atom and the calculations demonstrated the LT adsorption energy was increased significantly (Ead = -33.571 kcal.mol-1). However, the LT release study showed that the adsorption energy did not change efficiently upon protonation in acidic environment (Ead = -31.857 kcal.mol-1). Finally, the LT adsorption was investigated on B(OH)2-functionalized graphene. The calculations represented that the adsorption energy was -9.607 kcal.mol-1 which can be attributed to the possible hydrogen bonding between LT molecule and B(OH)2 functional group. The adsorption energy was changed to -1.015 kcal.mol-1 during protonation process. It can be concluded that the protonation of LT/B(OH)2-functionalized graphene complex in carcinogenic cells area, separates the LT from the nanocarrier. Thus, B(OH)2-functionalized graphene nanoflakes can be considered as a promising nanocarrier candidate for LT delivery.