This chapter examines the way in which Aristophanes introduces obscene words into his comedies both at the beginning of the plays and subsequently, following more heightened and/or more sober sequences. The Aristophanic norm is to introduce obscenity unsignalled, the 'obscenity out of nowhere' technique, often employed to signal abuse, crudeness, buffoonery and/or freedom from inhibitions. Alternatively, the poet sometimes employs the 'build-up' technique, in which double entendres and sexual allusions occur with increasing intensity before a climactic primary obscenity is finally introduced. Examples of both techniques are analysed, and some of the challenges that Aristophanic obscenity present and the relationship between obscenity and paratragedy are explored.