We prove the Marcinkiewicz-Zygmund Strong Law of Large Numbers for U-statistics of strictly stationary, absolutely regular observations (xi(i))(i >= 1).Under suitable moment conditions and conditions on the mixing rate, we show that n(-2+gamma) Sigma(1 <= i<j <= n) (h(xi(i), xi(j)) - Eh(xi, eta)) -> 0 for some gamma >= 0, in the non-degenerate case, and n(-1+gamma) Sigma(1 <= i<j <= n) (h(xi(i), xi(j)) - Eh(xi, eta)) -> 0 in the degenerate case. (C) 2009 Elsevier B.V. All rights reserved.