The paper discusses some negative aspects of the work of Poland’s customs system after the country’s entry to the European Union on May 1, 2004. The author attempts to explain the reasons for these shortcomings and also examines their social and economic implications. Negative developments in the Polish customs service have included misguided organizational changes that have led to conflicts among customs officers, Mosiej says. Another problem is corruption among customs administration employees, a trend that has risen considerably since the country’s EU accession, according to Mosiej. Other unsettling trends include decreased customs protection of the domestic market, a major drop in government revenue from customs duties, and the closure of many customs agencies and the resulting loss of jobs, the author says. All these negative trends have resulted from both exogenous and endogenous factors. The former include the adopted EU customs regulations, while the latter involve the activities of Polish customs officers themselves. All the negative aspects of the work of Poland’s customs system should be eliminated as soon as possible, Mosiej concludes, because this harms the image of the country’s customs system in the EU and elsewhere.