The subject of the present invention is the provision of new salts of duloxetine of the Formula (I) with organic acids, process for their preparation and medicinal products containing thereof. The new salts are essentially free from the impurity of the Formula (II) and possess high purity and high stability. The new duloxetine salts are prepared by reacting duloxetine free base dissolved in an organic solvent with an approximately equimolar amount of an organic acid. Particularly advantageous crystalline salts are those formed with fumaric acid, citric acid or (−)-mandelic acid.