On 15 October 1975, a decision was made in Warsaw to merge the previously separate towns of Kędzierzyn and Koźle into a single agglomeration called Kędzierzyn-Koźle. To be more precise, the new agglomeration consisted of four towns: Koźle, Kędzierzyn, Kłodnica, and Sławięcice. Aside from them, the new town included the villages of Lenartowice, Miejsce Kłodnickie, and Cisowa.
The primary argument in favor of such a solution was the increase of the significance of the towns in the Opole Voivodeship, which were rather small at that time. The total number of the inhabitants of Kędzierzyn-Koźle placed the new town second to Opole among other cities in the voivodeship, which rightfully caused the expectation of the allocation of funds appropriate to this fact.
During the existence of the Polish People’s Republic (PRL), the structures of the Polish United Workers’ Party (PZPR) was much more significant than the administration. Therefore, the obvious sign confirming the impending merge was the event of May 1975, when the municipal committees of PZPR in Kędzierzyn, Sławięcice, and Kłodnice, as well as the County Committee of the Party in Koźle, were merged into a single town committee of PZPR. The burden of the integrating works was imposed on the then-heads of the towns: Jerzy Wantuła of Kłodnica, Jerzy Berduszek of Koźle, Julian Wieczorek of Sławięcice, and Stanisław Biernat of Kędzierzyn. The latest of the four assumed the role of the supervisor of the integrating team.
The merge of the towns brought expected benefits and the increase of the developmental possibilities. The town budget doubled in comparison to that from before the merge. The scope of urban transport increased. The almost 1000-year tradition of the Middle-Age Koźle was merged with the modern Kędzierzyn, where the chemical industry was developing well and more sports venues, service facilities, and cultural sites were built. Virtually every neighborhood features historic parks, and the forests within the town’s borders occupy the area of 697 hectares, whereas the meadows and pastures – 465 hectares.
Due to the creation of Kędzierzyn-Koźle, when it comes to the total area, our town leads the way in the Opole Voivodeship (123.4 km2). At the end of 1975, the total number of the inhabitants was 69,285.
Several months earlier, on 28 May 1975, a new, two-tier administrative division of the country was introduced, which abolished the previously existing counties, including Koźle County.