Imidacloprid (1[(6-chloro-3-pyridinyl) methyl]-N-nitro-2-imi- dazolidinimine, chloronicotyl (CAS No: 105827-78-9)), neonicotinoid insecticide, is an extensively used insecticide for crop protection in the world wide from the last decade due to its low soil persistence and high insecticidal activity at low application rate. The acute and sublethaleffects ofimidacloprid on non-target organisms are not well known on aquatic life. The aim of the present study is to determine the histopathological effects of sublethalimidacloprid on the standard non-target test organism, Tilapia (Oreochromisniloticus). Experiments were conducted at two concentrations (50 and 100 mg/Limidacloprid) with two control groups (control and control with acetone). 60 L glass aquariaswere used with aeration. The mean weight and length of tilapia were 34.07± 1.49 g and 12.85±0.18 cm, respectively. After exposure to 24 and 96 h to sublethalimidacloprid concentrations, the fish were sacrificed under ice anesthesia and fixed with buffered 10% formalin. Routine histological procedures were processedand tissue sections were stained with H&E. Following exposure to sublethalimidacloprid caused some lesions on gill and liver tissues. There is no significant histopathological findings were observed on the other tissues when compared to control groups. Gill tissues showed hyperemia, epitelial lifting, fusion of secondary lamellae and talengiectasia, whereas hyperemia and hydropic degeneration were observed in the liver tissues. Imidacloprid was affected on cellular level even in sublethal concentrations