The family Cyprinidae can be found in almost all Indonesian rivers, including the Banjaran River, Banyumas Regency. Leukocyte differential aims to determine the difference in the percentage of leukocytes. This study was to determine the relationship between sampling locations (upstream, middle, and downstream) with differential leukocytes and to determine the picture of blood smears from several species of fish in the family Cyprinidae. Sampling using purposive sampling technique at three different stations. The data obtained were analyzed using the Analysis of Variance (ANOVA) method with an error rate of 5% and a description of the results of microscopic observations of the types of leukocytes. The results showed that the comparison of the percentage of leukocytes in nilem fish (Osteochilus vittatus), brek fish (Barbonymus balleroides), and lunjar fish (Rasbora argyrotaenia) with locations Upstream, Middle, Downstream of the Banjaran River, Banyumas, was significantly different (p<0.05). The highest percentage of leukocyte cells is in the Downstream zone in the Banjaran River, Banyumas, namely neutrophil cells and monocyte cells. The percentage of neutrophil cells for Nilem Fish was 9.5%, Brek Fish 8.5%, and Lunjar Fish 9.4%. The percentage of monocyte cells in Nilem Fish was 8.9%, Brek Fish 8.7%, and Lunjar Fish 8.5%. Neutrophil cells have a finely granular cytoplasm and a segmented nucleus in the center. Eosinophil cells have a redder cytoplasm, the nucleus is located elongated at the edge of the cell, has large granules. Lymphocyte have a dark blue cytoplasm, and a round to oval nucleus. Monocytes have pale blue cytoplasm and the shape of the nucleus varies from kidney-shaped to two large lobes.