000 Mathematics Subject Classification: Primary 16R50, Secondary 16W55.We present some results about the Z2-graded polynomial identities of block-triangular matrix superalgebras R[[A M],[0 B]]. In particular, we describe conditions for the T2-ideal of a such superalgebra to be factorable as the product T2(A)T2(B). Moreover, we give formulas for computing the sequence of the graded cocharacters of R in some interesting case.Partially supported by MURST COFIN 2003 and Università di Bari.