Let X_\phi and X_\psi be projective quadrics corresponding to quadratic forms \phi and \psi over a field F . If X_\phi is isomorphic to X_\psi in the category of Chow motives, we say that \phi and \psi are motivic isomorphic and write \phi\stackrel{m}\sim\psi . We show that in the case of odd-dimensional forms the condition \phi\stackrel{m}\sim\psi is equivalent to the similarity of \phi and \psi . After this, we discuss the case of even-dimensional forms. In particular, we construct examples of generalized Albert forms q_1 and q_2 such that q_1\stackrel{m}\sim q_2 and q_1\not\sim q_2 .