Scientists emphasize the enormous potential of new sources of bioactive compounds to combat global diseases. One of the most important of these sources is the endophytic fungi. They are defined as fungi that asymptomatically colonize intracellular spaces within plant tissues. The biodiversity of these fungi, which have a symbiotic relationship with the plant, is impressive. In addition, the bioactive substances produced by these endophytic fungi are shaped by the characteristics of the plant with which they are in contact. Fungal endophytes produce beneficial and invaluable bioactive metabolic compounds with anticancer, antimicrobial, anti-inflammatory, insecticidal, antioxidant, etc. properties. Some of these bioactive compounds are terpenoids, phenolics, flavonoids, macrolides, alkaloids, steroids, polyketides, auxin, quinone, and indole acetic acid. Endophytic fungi have also been found to be used in agriculture and industries other than medicine. The potential of natural bioactive compounds obtained from endophytic fungi to be produced in large quantities using biotechnological processes and to offer more economical alternatives are also their positive aspects. Enzymes, biocontrol, and plant growth-promoting substances produced by endophytic fungi have shown that they have biotechnology potential and have made these organisms more popular. This chapter resumes the potential use of endophytic fungal bioactive compounds for human welfare by highlighting the richness of these organisms in terms of natural biological products.