We demonstrate that the thickness increase of the porous layer on p-type (1-10 ohm-cm) silicon can be inhibited from hundreds to several nm/min in regular anodizing by exposure to He-Ne laser irradiation. During 2.0 mW laser irradiation, the growth in thickness was reduced to 5-6 nm/minute by anodizing with a current density of 10 mA/cm(2). The inhibition effect on the thickness increase of porous silicon depends significantly on the laser power during a fixed anodizing time. (C) The Author(s) 2016. Published by ECS. All rights reserved.