Endogenous endophthalmitis accounts for approximately 5 - 10% of all endophthalmitis cases. We report a case of a middle-aged gentleman with underlying uncontrolled diabetes mellitus who presented with fever and generalised body weakness for one week. He was diagnosed with invasive Klebsiella syndrome based on blood culture with presence of bilateral pleural effusion, liver abscess, renal impairment and sphenoidal sinusitis. The patient developed sudden bilateral painless reduced vision on day two of admission. Ocular examination revealed bilateral severe anterior chamber reaction and severe vitritis that obscured the view of the fundus. Ocular B-scan ultrasonography showed multiple loculations in the posterior segment in both eyes. There was soft tissue density with calcification in the left sphenoid sinus on computed tomography of the orbit. He was treated for bilateral endogenous endophthalmitis with multiple intravitreal antibiotic injections, but showed no improvement. Functional endoscopic sinus surgery was performed and revealed that the left sphenoid sinus was filled with fungal balls. Following drainage of sphenoidal pus, there was resolution of vitritis and fundus examination showed features of underlying fungal infection with a "string of pearls" present along the vascular arcade of both eyes. The patient was diagnosed with bilateral endogenous endophthalmitis secondary to invasive Klebsiella syndrome with coexisting fungal endophthalmitis secondary to sphenoid mycetoma. In addition to repeated intravitreal antibiotic injections, he was also treated with systemic and topical antifungal therapy. At three months post treatment, the infection resolved and his vision improved from counting fingers to 6/36 bilaterally. Key messages: A middle-aged gentleman presented with bilateral endogenous endophthalmitis secondary to invasive Klebsiella syndrome with coexisting fungal endophthalmitis secondary to sphenoid mycetoma. A high index of suspicion is required for early diagnosis of fungal endophthalmitis.