ABSTRACT. An injective function f : V (G) → {L1, L2, . . . , Ln}, where Lj is the jth Lucas number (j = 1, 2, . . . , n) is said to be Lucas cordial labeling if the induced function f ∗ : E(G) → {0, 1} defined by f ∗(uv) = (f(u) + f(v)) (mod 2) satisfies the condition |ef (0) − ef (1)| ≤ 1, where ef (0) is the number of edges labeled with 0 and ef (1) is the number of edges labeled with 1. A graph which admits Lucas cordial labeling is called Lucas cordial graph.