This study was carried out to determine the effects of Protim WR-230 and imersol aqua impregnation materials on the adhesion strength for synthetic, yatex and hickson decor varnishes in the Scots pine (Pinus sylvestris L.), Oriental beech (Fugus orientalis lipsky.) and white oak (Quercus petreae L.) woods. Before varnishing process, the test samples were impregnated according to the procedure in ASTM-D 1413-76 standards. And then, impregnated samples were varnished according to the ASTM-D 3023 principles. Finally, Samples were exposed to the effects of exterior factors for 12 months. The surface adhesion strength of test samples was determined according to ASTM-D 4541 and TS 24624 principles. As a result; the highest adhesion strength was determined as 4.153 MPa on the control samples of Scots pine processed with synthetic varnish and the lowest as 1.359 MPa on the white oak wood processed with Protim WR-230 with yatex varnish at the end of the fourth season. The adhesion strength for varnishes was decreased by approximately 13% in the first season, 16% in the second season, 26% in the third season, 35% in the fourth seasons, respectively. (c) 2006 Elsevier Ltd. All rights reserved.