The present study was conducted to investigate the effectiveness of lycopene in alleviating the toxicity of cypermethrin (CYP) on haematological parameters in carp, Cyprinus carpio. Fish (totally 140 fish) were exposed to sublethal concentrations (0.202 and 0.404 μg/L) of CYP, and lycopene (10 mg per kg of fish weight) was simultaneously administered. At the end of 28 days administration, blood samples were collected and haematological changes (red and white blood cell count, haemoglobin concentration, haematocrit level, and erythrocyte indices: mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration) were determined. According to the data obtained, CYP was determined to lead to negative alterations in the haematological parameters investigated. The administration of lycopene alleviated this effect.