Abstract. Let y(h) (t, x) be one solution towith a non-homogeneous term h, and y| (0,T )×∂Ω = 0, where Ω ⊂ R n is a bounded domain. We discuss an inverse problem of determining n(n + 1)/2 unknown functions aij.., h 0 suitably, where Γ0 is an arbitrary subboundary, ∂ν denotes the normal derivative, 0 < θ < T and 0 ∈ N. In the case of 0 = (n + 1) 2 n/2, we prove the Lipschitz stability in the inverse problem if we choose (h1, ..., h 0 ) from a set H ⊂ {C ∞ 0 ((0, T ) × ω)} 0 with an arbitrarily fixed subdomain ω ⊂ Ω. Moreover we can take 0 = (n + 3)n/2 by making special choices for h , 1 ≤ ≤ 0. The proof is based on a Carleman estimate.Mathematics Subject Classification. 35R30, 35K20.