Sufficient conditions are obtained for the existence of positive perodic solutions of the following mtegrodifferentnal model of mutualism dt dN1(t)=r1(t)N1(t) [1+∫∞o J1(s)N1(t-s)ds K1(t)+a1(t)∫∞oJ2(s)N2(t-s)ds-N1(t-ó1(t))], dt dN2(t)=r2(t)N2(t)[1+∫∞oJ1(s)N1(t-s)dsK2(t)+a2(t)∫∞oJ1(s)N1(t-s)ds-N2(t-ó2(t))], where r2, K2, a2, σ2, 2=1, 2 are positive continuous w-permdm functmns, a2>K2, 2=1, 2, Jτ ∈ C ([0, ∞], [0, ∞)), and ∫∞ J2(s)ds=1, 2=1, 2