The present invention is directed to golf balls having a resilient inner core and outer core made of a material substantially free of fillers. The invention also encompasses golf balls wherein the inner and outer cores are not made of a thermoplastic material. The invention encompasses golf balls having an inner core, an outer core, an inner cover, and an outer cover wherein the inner core has a specific gravity ρ12, the outer core has a specific gravity ρ14, the inner cover has a specific gravity ρ16, and the outer cover has a specific gravity ρ18, wherein the relationship between the specific gravities is expressed by the mathematical expression: ρ16≧ρ18≧ρ14≧ρ12.