Abstract.We study large time asymptotic behavior of solutions to the periodic problem for the nonlinear damped wave equationwhere Ω = [−π, π] , α, β, λ, σ > 0. We prove that if the initial data φ ∈ H 1 and ψ ∈ L 2 , then there exists a unique solution u (t, x) ∈ C [0, ∞) ; H 1 of the periodic problem which has the time decay estimatesfor all t > 0. Moreover under some additional conditions we find the asymptotic formulas for the solutions. Mathematics Subject Classification (2000). 35L15, 35K20.