Machine and method for producing electronic-cigarette cartridges; being provided: a fill conveyor which feeds bottom shells of the cartridges along a fill path; a filling device located along the fill path to feed a measure of a liquid substance downwards into each bottom shell; an assembly conveyor which feeds bottom shells along an assembly path; a transfer station where the bottom shells are transferred from the fill conveyor to the assembly conveyor; and at least a first assembly device located along the assembly path to fit each bottom shell with a corresponding top cap.