f : ∪A → ρ is called a conflict free coloring of the set-system A (with ρ colors) ifThe conflict free chromatic number χCF (A) of A is the smallest ρ for which A admits a conflict free coloring with ρ colors.A is a (λ, κ, μ)-system if |A| = λ, |A| = κ for all A ∈ A, and A is μ-almost disjoint, i.e. |A ∩ A | < μ for distinct A, A ∈ A. Our aim here is to studyfor λ κ μ, actually restricting ourselves to λ ω and μ ω.For instance, we prove that • for any limit cardinal κ (or κ = ω) and integers n 0, k > 0, GCH implies χCF (κ +n , t, k + 1) = κ +(n+1−i) if i · k < t (i + 1) · k, i = 1, . . . , n; κ if (n + 1) · k < t;• if λ κ ω > d > 1, then λ < κ +ω implies χCF (λ, κ, d) < ω and λ ω (κ) implies χCF (λ, κ, d) = ω;• GCH implies χCF (λ, κ, ω) ω2 for λ κ ω2 and V = L implies χCF (λ, κ, ω) ω1 for λ κ ω1;• the existence of a supercompact cardinal implies the consistency of GCH plus χCF (ℵω+1, ω1, ω) = ℵω+1 and χCF (ℵω+1, ωn, ω) = ω2 for 2 n ω;• CH implies χCF (ω1, ω, ω) = χCF (ω1, ω1, ω) = ω1, while MAω 1 implies χCF (ω1, ω, ω) = χCF (ω1, ω1, ω) = ω. * Corresponding author.† The preparation of this paper was partially supported by OTKA grants K 61600 and K 68262.