Abstract. Let X be a zero-dimensional compact metrizable space endowed with a strictly positive continuous Borel σ-additive measure µ which is good in the sense that for any clopen subsets U, V ⊂ X with µ(U ) < µ(V ) there is a clopen set W ⊂ V with µ(W ) = µ(U ). We study σ-ideals with Borel base on X which are invariant under the action of the group Hµ(X) of measure-preserving homeomorphisms of (X, µ), and show that any such σ-ideal I is equal to one of seven σ-ideals:Here [X] ≤κ is the ideal consisting of subsets of cardiality ≤ κ in X, M is the ideal of meager subsets of X, N = {A ⊂ X : µ(A) = 0} is the ideal of null subsets of (X, µ), and E is the σ-ideal generated by closed null subsets of (X, µ).