Mercury intrusion porosimetry (MIP) on archaeological potteries classified as Belen fine and ordinary types from Catamarca, Argentina, was analysed. The MIP technique allowed identifying high percentage of uniform pore size in fine pottery, and inhomogeneous pore size in ordinary pottery. Fragments of neck and body sections of the same ordinary vessel were also studied. The porosity of the body section was smaller than the one of the neck, and the cumulative pore volume curve analysis of the body sectors (of the same vessel) evidenced that some pore sizes were sealed partially with respect to the one of the neck. Such behaviour may provide evidence of physical or chemical transformations from their manufactured process, during their use, and post-depositional effects.Fil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comision de Invest.científicas. Centro de Tecnología de Recursos Minerales y Ceramica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Tecnología de Recursos Minerales y Ceramica; ArgentinaFil: Zagorodny, Nora Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Análisis Cerámico; Argentina