The morphological characteristics and haematological studies were studied in fifteen male albino rats (Wistar Strain) aged between 12 and 14 weeks and with a body weight of 150 - 180g. The rats were allowed to feed on commercially prepared rat pellet and provided with fresh water ad libitum. The rats were divided into three groups; the rats were in groups A, B and C of 5 rats each. Group A served as control of the study; Group B was treated with Chloramphenicol at the dose rate of 25mg/kg body weight per os for 20 days; while Group C was treated for 25 days. Semen used in this study was obtained from the caudal epididymides while morphological aberrations were determined from spermatozoa counted after stained with Wells and Awa stain. Results of the spermiogram showed that the volume was decreasing as the prolonged dosage of chloramphenicol increases. The percentage motility in Group A (89.0 + 2.45%), differed significantly (p < 0.05) when compared to Group B (72.0 + 3.74%) and Group C (66.0 + 2.45%). The same pattern is observed in percentage liveability, morphological aberration and sperm concentration. This indicates that prolonged dosage of chloramphenicol will cause infertility in male animals. It is therefore concluded and recommended that prolonged dosage of chloramphenicol can cause infertility and or sterility. So it should not be used in male animals meant for mature breeding and artificial insemination programme.