The physical properties of a new family of cubic UX 2 Zn 20 ( X = Co , Rh , Ir ) heavy-fermion compounds are presented. Both UCo 2 Zn 20 and URh 2 Zn 20 show peaks in specific heat and magnetic susceptibility at ∼ 5 – 10 K suggesting the presence of crystalline electric field (CEF) effects in these materials, i.e., a localized 5 f 2 configuration of uranium. UIr 2 Zn 20 exhibits a first-order ferromagnetic transition at T c = 2.1 K with a saturation moment μ sat = 0.4 μ B at 2 K indicating itinerant ferromagnetism. All compounds in this series are heavy-fermion materials with enhanced electronic specific heat coefficients γ ∼ 100 – 450 mJ / mol K 2 .