The cultural transition from the Mesolithic to Neolithic in the Rhône valley has been radically illuminated by excavation in the Grotte du Gardon (Ain). Examination of the well-stratified assemblages shows that flint and pottery associated with early Neolithic cultures in the Mediterranean occurred with lithics of local Mesolithic traditions. The author proposes that during the transitional period in this region in the sixth millennium BC, peoples of the two cultures lived side by side.