ABSTRACT: Seafood is one of the most important sources of nutrients. However, they have a short shelf-life and the traditional preservation methods may generate losses in their natural flavour and nutrients. Thisstudy evaluated and optimize the High Pressure Processing (HPP) regarding pressure level (200-400 MPa) and holding time (0-5 min) applied to lion’s paw scallop (Nodipecten nodosus) to reduce microbial contamination while maintaining desirable characteristics. Response surface methodology with a Box-Behnken design and Desirability function were employed to simultaneously optimize these quality attributes. HPP enhanced microbial quality at 200 MPa/5 min, despite promoting inadequate physical-chemical modifications in the adductor muscle of the scallop. In such processing condition, in spite of a slight increase in muscle humidity which could be of benefit, pH increase was also verified, as well as a decrease in water holding capacity (WHC). At more severe level (400 MPa/5 min), a decrease in the shear force related to instrumental texture and in Whiteness (W) and Luminosity (L*) related to color was observed. Simultaneous optimization provided a value of 365MPa / 2min where physicochemical characteristics would be the more similar to the scallop without facing a preservation process.