The authors report a case of 14-year-old boy presented to the Ophthalmologic Department of University Hospital in Olomouc with the diagnosis af acute anterior uveitis. A living parasite has been detected in the anterior chamber in a slit lamp examination. The vitreous and retina remained uninvolved. The acute iridocyclitis associated with parasitic infection is a very rare cause of anterior uveitis in Central Europe. The patient underwent surgical removal of the parasite via paracentesis. The inflammation resolved under the treatment with atropine and dexamethasone drops within a few days. Histopathological examination revealed the parasite as a young larval stage of tapeworm from family Pseudophyllidea (sparganum). Based on the analysis of development cycles of different types of tapeworms and according the literature data on tapeworms found in the Czech Republic genus Spirometra seemed to be the most plausible cause of the patient's disease. As the most probable source of viable parasites authors suspect swallowed water containing tiny infected crustaceans in the dam near the town Olomouc in Moravia.