设等差数列{an}的公差为d,∵等差数列{an}中S4+a25=5,∴4a1+ 4×3 2 d+a1+24d=5,∴a1+6d=1,即a7=1,∴S13= (a1+a13)×13 2 =13a7=13,故选:D.