A perfect Roman {3}‐dominating function on a graph G = (V, E) is a function f : V⟶{0, 1, 2, 3} having the property that if f(v) = 0, then ∑u∈N(v)f(u) = 3, and if f(v) = 1, then ∑u∈N(v)f(u) = 2 for any vertex v ∈ V. The weight of a perfect Roman {3}‐dominating function f is the sum ∑v∈Vf(v). The perfect Roman {3}‐domination number of a graph G, denoted by , is the minimum weight of a perfect Roman {3}‐dominating function on G. In this paper, we initiate the study of a perfect Roman {3}‐domination, and we show that the decision problem associated with a perfect Roman {3}‐domination is NP‐complete for bipartite graphs. We also prove that if T is a tree of order n ≥ 2, then and characterize trees achieving this bound, and we give an infinity set of trees T of order n for which approaches this bound as n goes to infinity. Finally, we give the best upper bound of for some classes of graphs including regular, planar, and split graphs in terms of the order of the graphs.