This study evaluated the effects of consuming contaminated Clarias gariepinus fish on the haematological parameters of Wistar albino rats. Twenty- four adult male rats were randomly assigned to four groups I, II, III, IV (n = 6 per group). These rats were fed ad libitum for 90 days with a diet composed of wild Clarias gariepinus fish from the two different river bodies admixed with commercial rat pellet. Group I served as controls, while Group II rats ingested Clarias gariepinus fish from the polluted Nun river. Group III consumed fish from Otamiri river, while Group IV was fed 100g of polluted fish from Nun river along with 1mg of Vitamin C per 100g of body weight dissolved in drinking water. Results showed that group II rats exhibited a significant reduction in haemoglobin concentration (8.70 ± 0.26 g/dl) compared to Groups I, III, and IV rats (10.32 ± 0.41 g/dl, 10.28 ± 0.14 g/dl, and 12.96 ± 1.3 g/dl) respectively at P < 0.05. Haematocrit value was significantly reduced in Group II rats (43.17 ± 0.90 %) compared to groups I, III and IV (45.55 ± 0.37, 48.21 ± 2.3, 49.5 ± 1.9) % respectively at P < 0.05. Erythrocyte count significantly reduced in Group II rats (2.63 ± 0.70 × 106/µL) compared to groups I, III and IV (3.30 ± 0.20, 3.59 ± 0.36, and 5.75 ± 0.6 × 106/µL) respectively at P < 0.05. White Blood Count was markedly increased in group II rats (4.46 ± 0.15) compared to I, III and IV (3.54 ± 0.18, 3.90 ± 0.02, and 3.65 ± 0.03) respectively at P < 0.05. The lymphocyte and eosinophil counts in group II were significantly elevated (7.49 x 10 cells/mm3 and 1.5 x 0.24 x 10 cells/mm3) compared to groups I (3.35 x 10 cells/mm3 and 0.5 x 10 cells/mm3), group III (3.6 x 10 cells/mm3 and 0.6 x 10 cells/mm3) and group IV (4.23 x 10 cells/mm3 and 0.3 x 10 cells/mm3) at P <0.05. there were no significant differences in neutrophil, basophil and monocyte counts. Mean corpuscular volume and mean corpuscular hemoglobin values were also significantly increased in groups II, III and IV rats (88.7 ±0.15 and 29.8 ±0.41, 62.5 ±0.42 and 25.5 ±0.31, and 57.2 ±0.31 and 28.5 ±0.40) mm3 to group I rats (41.3 ±0.28 and 21.1 ±0.60) mm3 at P < 0.05. However, there was a significant rise in the mean corpuscular volume of group II rats compared to groups III and IV at P < 0.05. Conversely, the mean cell hemoglobin concentration was elevated in group I rats (26.4 ±1.2 mm3) compared to experimental groups II, III and IV respectively (21.4 ± 0.87, 22.9 ± 0.94 and 23.7 ± 0.70) mm3. This study probably indicates that some haematological parameters are adversely affected among rats exposed to cadmium and iron polluted African catfish from a Southern Nigeria River.