Common octopus (Octopus vulgaris CUVIER, 1797) is a very valuable fishery resource, and also plays a
significant role in trophic dynamics in ecosystems where is present, so it is important to undertake parasitological studies on
it, particularly scarce in Venezuela. Fifty two adult specimens of common octopus, from fishing activities on the Northeast
at Margarita Island, were studied in order to establish their health status. Due to the presence of iridescent nodules at different
organs, tissue samples were taken, fixed with Bouin´s solution and histologically processed. Histopathologic analysis showed
the coccidia Aggregata sp., wich was no previously recorded in venezuelan waters. Between the parasitic life stages observed,
the most interesting taxonomically were oocysts, wich were sub-spherical to ovoid in shape, with smooth surface and 614.3
mm in average diameter (360-1060 mm), as well as sporocysts, spherical and measuring 12.3 mm as mean (11.2-14 mm),
containing 4 to 12 vermiform sporozoites, with a mode of 6. Some taxonomic, ecological and pathological issues are
discussed.