New bideterminantal formulas for the irreducible symplectic and orthog
onal characters are given that generalize the classical bideterminanta
l formulas. These formulas are analogous to Regev's (Israel J. Math. 8
0 (1992), 155-160) bideterminantal formulas for Schur functions, the i
rreducible general linear characters. Also, new bideterminantal formul
as for Proctor's intermediate symplectic characters are derived.