The objective of this study is to evaluate effect of various machining techniques on the surface roughness of beech (Fagus orientalis) and aspen (Populus tremula) lumber. Surface characteristics of sawn, planed, and sanded samples of both species were determined employing a stylus type profilometer. Average roughness (R-a), mean peak-to-valley height (R-z), core roughness depth (R-k), reduced peak height (R-pk), and reduced valley depth (R-vk) roughness parameters were used to determine surface characteristics of the samples. Based on the results of statistical analysis, measurements taken from the surface in tangential and radial directions of both species did not result in significant difference at a 95% confidence level. However, significant statistical difference was found between surface characteristics of aspen and beech samples, machined with four different ways in both grain orientations. This study suggests that stylus method can be successfully used to evaluate and distinguish variations on the surface of wood, due to grain orientation and planning and sanding. Data generated in this study can be used as a quality control tool for further processes such as finishing or gluing of wood from two species. (C) 2005 Elsevier Ltd. All rights reserved.