Background <p><i>Acremonium sclerotigenum</i> exhibits antagonistic properties against various detrimental organisms, including bacteria, nematodes, and mites. As the predominant species within the <i>Acremonium</i> genus, it is characterized as an opportunistic pathogenic fungus that commonly inhabits soil and plants as a saprotroph. Additionally, it has been identified as the etiological agent of superficial infections, such as onychomycosis, and, less frequently, invasive infections.</p> Case presentation <p>This study presents a unique case involving a 79-year-old male who developed peritoneal dialysis-associated peritonitis (PDAP) attributed to <i>Acremonium sclerotigenum</i>. To the best of our knowledge, this represents the first documented instance of PDAP caused by this fungal species.</p> Conclusion <p>The identification of pathogens is essential for diagnosing PDAP.</p>