F: ℝ2 → ℝ2 is an almost-area-preserving map if: (a) F is a topological embedding, not necessarily surjective; and (b) there exists a constant s > 0 such that for every measurable set B, μ(F(B)) = sμ(B) where μ is the Lebesgue measure. We study when a differentiable map whose Jacobian determinant is nonzero constant to be an almost-area-preserving map. In particular, if for all z, the eigenvalues of the Jacobian matrix DFz are constant, F is an almost-area-preserving map with convex image. © 2010, Sociedade Brasileira de Matemática.