A new gregarine pathogen from Altica hampei (Allard, 1867) has been reported (Coleoptera: Chrysomelidae) for the first time in Turkey. A. hampei causes considerable damage on Cirsium arvense (L.) Scop. (Asterales: Asteraceae). Therefore, detection of pathogens in which may be a biological control agent of A. hampei was aimed. Overall, 134 A. hampei adults were collected from Ordu province of Turkey from April to June of 2016. During the study, gut content of adults was examined thoroughly using a light microscope. Total infection rate was found as 1.5%. Different life stages of the gregarine pathogen, gamont, associative form, trophozoite, cyst and precyst were observed in the midgut of adults. Observed pathogen was a cephaline gregarine. The morphological features, characteristic measurements and ratios of the observed gregarine were not validation for the definition of species level. Up to the present, since there are no reports about presence of gregarine pathogen from A. hampei, the observed pathogen from A. hampei was significant as the first gregarine pathogen report for Turkey and for the world literature. Besides, observed gregarine pathogen in present study is a contribution to the pathogen biodiversity of Turkey.