* Cave lion: *Panthera leo spelaea* was a lion species that lived in Europe and Asia during the Pleistocene epoch. They were larger than modern lions, reaching about 1.2 meters tall at the shoulder and weighing up to 350 kg (770 lb).
* Saber-toothed cat: This is a broad term, as there were many species of saber-toothed cats. The most famous is the Smilodon genus, particularly the Smilodon fatalis. Smilodon was taller than cave lions, reaching 1.4 meters at the shoulder, but was lighter on average, weighing up to 280 kg (620 lb).
So, who's bigger?
* Cave lions were heavier.
* Smilodon (saber-toothed cats) were taller.
It's a close call, but it really depends on what you consider "bigger."