Myxobolus ichkeulensis is one of the species fish parasites within the class Myxozoa that infests the gill filaments of grey mullet (Mugil cephalus). M. ichkeulensis infestation rates vary depending on environmental conditions and seasonal variations. In this research, seasonal infestation ratio of M. ichkeluensis on Grey Mullets living in 4 different environmental conditions, were determined. To accomplish this aim, 25 Grey Mullet individuals were captured monthly from 4 different stations (Karataş Port, Hurma Boğazı Lagoon, Çamlık Lagoon and Yumurtalık Port) within the coastal region of Adana province. In addition, relation between infestation ratio and the following parameters: fish size (length and weight); season and salinity were investigated. Our results revealed that, 109 fish infested out of 1200 fishes (%9.08) by M. ichkeulensis; Highest infestation level (%35.8) was recorded in summer months (July-September) interval. Parasitic cyct settlement on the gill arches was determined to be with the highest rate (48.2%) on the fist arc. The highest infestation level (21%) was recorded in Grey Mullets captured from Yumurtalık Port in comparison to other stations studied.