Supercritical CO2 can be used as anti-solvent in many processes. It permits to micronize molecules dissolved in an appropriate organic solvent. In this work, Griseofulvin has been chosen as solute to be micronized using a Supercritical Anti-Solvent process type. The aim is to validate and compare a new mixing device based on the impinging jets technology. This technique consists of arranging two jets in face to face position in order to generate a zone of high turbulence and favour the mass transfer. Experiments have been conducted at 10 MPa and 343 K. Injection velocities have been varied from 0.7 to 13 m s(-1) and the geometric factor from 4 to 27. This work permits to bring to the fore the significant influence of operating parameters and geometric parameters of the impinging jets device, (jets velocity, impinging distance, organic solvent, solute concentration) on particle size and particle size distribution. Compared to traditional SAS process, this device allows a significant reduction on particles size from few millimetres to 10 mu m. The use of this new device seems to have a significant interest. (C) 2008 Elsevier B.V. All rights reserved.