Endophytic fungi, which reside asymptomatically within plant tissues, play a crucial role in the ecological fitness and medicinal properties of their host plants. This study investigates the isolation and diversity of endophytic fungi associated with Costusspeciosus, a medicinal plant known for its wide range of pharmacological uses. Plant samples, including leaves and stems, were collected and subjected to surface sterilization, followed by fungal isolation on Potato Dextrose Agar (PDA). Morphological characterization was employed for fungal identification. A total of 09 fungal species were isolated, representing diverse genera such as Aspergillus, Penicillium, and Fusarium,  among others. Diversity indices, including Shannon-Wiener and Simpson's indices, revealed a high fungal diversity within the host tissues, with a dominance of (specific endophytic taxa) in different plant parts. Phylogenetic analysis confirmed the distinct clustering of isolates, suggesting varying ecological roles. The results indicate that these endophytic fungi may contribute to the bioactive properties of Costus speciosus, potentially enhancing its medicinal value. Further research is needed to explore the bioactive compounds produced by these fungi and their potential applications in pharmaceuticals.