Let A and B be C * -algebras. We prove the slice map conjecture for ideals in the operator space projective tensor product A ⊗ B. As an application, a characterization of the prime ideals in the Banach * -algebra A ⊗ B is obtained. In addition, we study the primitive ideals, modular ideals and the maximal modular ideals of A ⊗ B. We also show that the Banach * -algebra A ⊗ B possesses the Wiener property and that, for a subhomogeneous C * -algebra A, the Banach * -algebra A ⊗ B is symmetric.2010 Mathematics subject classification: primary 46L06; secondary 46L07, 47L25.