Investigation was carried out to assess and compare the seasonal changes of some haematological parameters in naturally infected and uninfected roach (Rutilus rutilus) with Cryptobia tincae. Prevalence of Cryptobia tincae was 17.8 % in winter, 25 % in spring, 17.9 % in summer and 16.3 % in autumn. On average, between 0.1 and 0.2 parasites per microscopic field were noted at 100× magnification. No statistically significant differences were observed for erythrocyte, leucocyte, haematocrit values between parasitized and unparasitised roach for each season (p> 0.05), except for haematocrit in autumn (p< 0.05). Seasonally, the significant differences were found for erythrocyte and haematocrit both infected and uninfected roach while it was not found for leucocyte. In the leucocyte profiles, the significant differences were estimated for neutrophiles in spring, for eosinophiles in autumn between infected and uninfected roach (p < 0.05).