Copper-ethanolamine based wood preservatives are the most important products for protection of wood in use class III and IV applications according to EN 335/1-2 standard. These preservatives can be applied using different procedures. One of them is dipping, predominantly used method in less industrialised countries. The most important parameter influencing the quality of this treatment is dipping time. Influence of various dipping times on copper retention, adsorption, penetration, colour of the specimens and copper fixation was examined. Copper-ethanolamine solutions of 2 different concentrations were utilised (cCu = 0.05 or 0.25 %). The results showed that longer dipping treatments resulted in higher retentions, better penetrations and lower leaching out copper-ethanolamine based wood preservatives from Norway spruce wood. After 1 week of dipping, on average samples retained 275 kg/m3 of preservative solution, copper active ingredients penetrated 3 mm into the specimens, and only 2.3 % of copper was emitted from samples impregnated with aqueous solution of the higher concentration, according to ENV 1250-2 leaching procedure.