The accession of the Slovak Republic to the European Union and the permanent pressure of competitive environment in which the companies of the Slovak poultry industry are also involved have a significant influence on the decisions made by the top management. If the companies want to keep up with new marketing conditions, they are forced permanently to improve production economy. One of the possibilities of improving the economy of poultry meat production is the introduction of new trends in poultry nutrition. Probiotics and their application through drinking water seem to be a good and thrifty option to improve performance, decrease mortality as well as feed consumption, and at the same time to keep high quality of poultry products. These facts were also confirmed by the results from our testing the Lactobacillus fermentum-based probiotic preparation in broiler chick fattening. According to these results, the tested probiotic preparation can be recommended for a wide range of applications in poultry nutrition. Its use has led to the productivity improvement from the aspect of an increase in produced meat and a decrease both in mortality and feed consumption, thus increasing the profit of poultry meat production.