OBJECTIVES: The aim of the study was to highlight the importance of histochemical processing of biopsy material in diagnosing fungal infections and the possibilities of particular histochemical methods in pathohistological diagnostics while providing insight into specific laboratory processing of biopsy material in fungal lesions which is important in the early detection of infections while also providing an overview of aspergillosis. STUDY DESIGN: This is a cross-sectional study in which 30 pathohistological samples from different patients were analyzed. All the patients as part of the study, in addition to their primary disease, were also diagnosed with a fungal lesion, in particular the aspergillosis-type lesion. SUBJECTS AND METHODS: The study included 30 patients suffering from a primary disease (diabetes, tumors, inflammation) in the period from 2010 to 2019. The same patients were suspected of having a fungal lesion or aspergillosis. Histopathological and histochemical methods were used throughout the study. To prepare the tissue for microscopy, a hematoxylin-eosin fixative was used. After tissue dehydration, the next step was fitting the sample to paraffin using xylene. Subsequently, thin sections of paraffin blocks were obtained using a microtome and placed on slides. The previous step involved microscopic analysis of finished histological specimens. To visualize the fungi, special staining was used: GOMORY staining and PAS staining. RESULTS: The results support the fact that out of 30 analyzed patients suffering from some chronic diseases with the consequences of fungal infections, the largest number are women, as many as 21 and only 9 men, and also the largest number of patients is older than 70 years. In all patients who were part of this study, in addition to the primary diagnosis, there was also a secondary diagnosis, a fungal infection. CONCLUSION: This study concludes that fungal infections (especially aspergillosis) most often occur in already immunocompromised patients.