In our research works dealing with polymer cristallization in severe conditions, recently we focused on high-pressure induced gamma-form nucleation in nucleated isotactic polypropylene (iPP). Alpha- and beta-nucleating agents (NAs) were selected. Gamma-form nucleation was investigated in isothermal and nonisothermal conditions [1,2]. The present work offers a new focus on crystal growth under hydrostatic pressure. It refers to an original optical high-pressure cell, named CRISTAPRESS, which has been especially designed to investigate liquid-solid transitions under elevated pressure [3]. The growth of the beta-form of iPP beta-nucleated with calcium pimelate (CaPim) was studied. The first results show the ability of CRISTAPRESS to follow in-situ crystallization in the beta-form in quiescent and isothermal mode explored in the ranges 10-50 MPa and 127-145 °C. CaPim nucleated efficiently the beta-form. The beta-crystal growth rate, depending on temperature and pressure, was successfully analyzed. Acknowledgement PAN/CNRS Collaborative Project n°179990 ‘High pressure crystallization and structure of polymers based nanocomposites’. CNRS, ARMINES, MINES ParisTech, Conseil Régional de Provence-Alpes-Côte d’Azur, and Conseil Général des Alpes-Maritimes for financial supports in the development of the «CRISTAPRESS» project. [1] Sowiński P., Piorkowska E., Boyer S.A.E., Haudin J.-M., Zapala K., Colloid Polym. Sci. 293 (2015) 665 [2] Sowiński P., Piorkowska E., Boyer S.A.E., Haudin J.-M., Eur. Polym. J. 85 (2016) 564 [3] Boyer S.A.E., Fournier F.E.J, Gandin Ch.-A., Haudin J.-M., Rev. Sci. Instrum. 85 (2014) 013906 / 029902