This paper explores the question of the design activity at the shop floor level. The design activity has been confined for a large part in the design and the methods office. However, a certain form of design adapted to the factory remains. It is necessary to solve the problems that appear during the manufacturing process and to improve the productivity. However another form of design can emerge; it has a stronger impact on the factory, since the rules of the manufacturing system are modified under its effect. The paper studies 21 cases of design in the Airbus factory at Saint-Nazaire. It shows that the design activity does exist at the shop floor level. It characterizes this activity distinguishing two types of design that can co-exist in a factory. It shows that the type of results reached is not the same according to the type of design implemented.