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 is encased by an outer core wherein the outer core has a volume greater than the inner core, inner cover, or outer cover and the inner core is made of a material substantially free of fillers. The volume relationship of the inner core (V12), outer core (V14), inner cover (V16), and outer cover (V18) is represented by the mathematical relationship: V14>⅗(V12+V16+V18), wherein V12≧V18≧V16. Also, 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≧ρ12≧ρ14.