The presence of the choir in the Opera increases in the second half of the eighteenth century on the thrust of reformist demands aimed at the hybridization of Italian and French melodramaturgy. The mechanisms of the impresarios’ system and its reception have not been adequately explored, even though they can explain the reasons for the growing importance that the choir obtained during the transition from post-metastasian Opera to romanticism. The article provides some quantitative data, referring above all to those theatrical centers that more than others hosted permanent groups of choristers, and gives a summary of the vision of the choir from the perspective of both treatise writers and theatre audience.