<p>Fertilizers containing the primary macronutrients, such as phosphorus (P) and potassium (K), constitute a significant group on the Polish market. However, in addition to their beneficial properties for plant development and proper growth, fertilizers can lead to environmental pollution with radionuclides. Therefore, the study aimed to analyze the activity concentrations of ^234,238U, ^226,228Ra, and ⁴⁰K isotopes in 38 mineral fertilizers available on the market. All samples contained phosphorus, and the largest analyzed group constituted multi-component fertilizers. The highest ²³⁴U and ²³⁸U activity concentrations were recorded in single and triple superphosphates containing the highest P₂O₅ content. Most of these fertilizers also contained elevated ²²⁶Ra concentrations. The highest ⁴⁰K activity concentrations were recorded in fertilizers containing the highest K₂O addition. The radioactive equilibrium between ²³⁴U&#xa0;and ²³⁸U isotopes is maintained (median: ²³⁴U/²³⁸U = 1.01), while isotope segregation between ²³⁸U and ²²⁶Ra occurs during fertilizer production (median: ²³⁸U/²²⁶Ra = 2.4). Calculated radioactive risk indicators for a significant part of the analyzed fertilizers exceeded acceptable limits; however, the annual effective radiation doses were still below the 1&#xa0;mSv limit. Furthermore, excessive soil fertilization can increase the concentration of radioactive isotopes in the soil, and consequently, in the human diet. To limit the amount of uranium transferred from the cultivated soil into groundwater and the human food chain, companies should undertake efforts to select low radioactive raw materials for fertilizer production.</p>