The mycobiome is an integral component of every living organism. Among other fungi associated with plants, endophytes are an interesting and favorable group of microorganisms, but information regarding them is still largely unknown. Wheat is the most economically significant and essential crop for global food security, which is exposed to a range of abiotic and biotic stresses. Profiling plants' mycobiomes can help in sustainable, chemical-reducing wheat production. The main objective of this work is to understand the structure of endogenous fungal communities in winter and spring wheat cultivars growing under different growth conditions. Further, the study attempted to investigate the effect of host genotype, host organs and plant growth conditions on the composition and distribution of fungi in wheat plant tissues. Comprehensive, high throughput analyzes of the diversity and community structure of the wheat mycobiome were performed, complemented by the simultaneous isolation of endophytic fungi, resulting in candidate strains for future research. The findings of the study revealed that the type of plant organs and growth conditions influence the wheat mycobiome. It was also assessed that fungi representing the genera Cladosporium, Penicillium, and Sarocladium form the core mycobiome of Polish spring and winter wheat cultivars. The coexistence of both symbiotic and pathogenic species in the internal tissues of wheat was also observed. Those commonly considered beneficial for plants can be used in further research as a valuable source of potential biological control factors and/or biostimulators of wheat plant growth.