We study the space–time symmetries and transformation properties of the non-commutative U(1) gauge theory, by using Noether charges. We carry out our analysis by keeping an open view on the possible ways θμν could transform. Since the theory is not invariant under the conformal transformations, with the only exception of space–time translations, we conclude that the most natural and dynamically consistent requirement is that θμν does not transform under any space–time transformation. A similar analysis should apply to other gauge groups.