The results are presented of hematological examinations of turkeys during fattening. A total of 60 clinically healthy turkeys of hybrid combination XK were examined, on days 1, 35, 94 of age both in female and male turkeys and on day 108 of age in male turkeys that were fattened to higher live weight. Tabs. I-IV show the results of hematological examinations including statistical data. The results document numerous variations in the values of hematological indicators with the growing age of fattened turkeys. Particularly some indicators of the red blood component showed a statistically significant increase in their average values (P < or = 0.01) with the growing age of turkey chicks: hemoglobin content increased from 84.47 milligrams to 106.34 milligrams, hematocrit value from 0.32 l/l to 0.36 l/l. No such relations were demonstrated in other indicators of the red blood component under investigation. Their average values in turkeys fluctuated within definite limits: from 1.82 to 2.54 T/l in total erythrocyte counts, from 25.22 to 30.48% in mean corpuscular hemoglobin concentration, from 39.58 to 46.62 pg in mean corpuscular hemoglobin and from 136.82 to 184.80 fl mean corpuscular volume. There were no significant differences between the males and the females in the particular indicators of the red blood picture. Unlike the red blood picture, the indicators of the white blood picture show much higher variability. In spite of the relatively high variability no relationships between their levels and turkey age or sex were demonstrated for the total leucocyte counts nor for the different types of leucocytes.(ABSTRACT TRUNCATED AT 250 WORDS)