Apparatus for and a method of filling a chain of successively connected bag containers, each closed at its bottom end with successive ones seamed at adjacent side edges, the chain defining sleeve means along the upper edge thereof, above said side seams. The invention comprises moving the chain of containers along a process line, from a source thereof to a discharge point, with said sleeve means uppermost, past a filling station having a filling head operable to charge flowable material received from a source thereof, from a filling nozzle of the filling head, into successive containers presented to the filling station and past a sealing station which is intermediate the sealing station and discharge point, the sealing station having sealing means for sealing the top of each filled container. The sleeve means is received onto a mandrel having a transverse bore at the filling station, the chain of bags is indexed along said process line, and the discharge nozzle moved in synchronism with indexed movement of the chain between an advanced position in which it projects into said transverse bore of the mandrel to fill a container and retracted position.