I currently carry 4 cards (Visa, Discover, DL, and University ID card) in one pocket, and a titanium credit card (keeps the wallet stiff and prevents bent cards), some business cards, and a guitar pick or two in the other pocket. With 4 cards I can easily get them in and out no problem. They'd almost fall out. I'd say you could get 6 cards on each side and still have no trouble sliding them in about out. Any more than that is doable, because leather stretches over time, but they'd be tucked in there pretty stiff.