||The objective of this thesis is to analyze the impact of complying with EU excise tax requirements on government revenues and demand of Czech and Slovak households. To estimate the tax influence the flow adjustment model is used for motor fuels and the partial adjustment model is used for addictive goods. Motor fuel tax has significant, although small, effect on demand in both countries. Household expenditures are barely affected by the cigarette taxation as tobacco companies absorb part of the tax and consumers switch to cheaper brands. The effect of past tobacco consumption on present demand is significant in both countries, but stronger in the Czech Republic. There is a good opportunity for both governments to collect even higher excise tax revenues in the future. These could cover the costs of externalities, if appropriately allocated.