Imidacloprid (IM) is a neonicotinoid insecticide being used extensively for crop protection and pet flea control programmes. However, IM is also a strong environmental toxicant for both animals and humans. As a result, the present study aimed to assess the ameliorative efficacy of Spirulina platensis (SP) aganist IM-induced oxidative stress and immune damage in broiler chickens. Chicks divided randomly into six equal groups (17 each). Group I administered filtered water orally for 4 weeks. Group II administered IM 10 mg/kg b.wt orally daily for 4 weeks. Group III given Spirulina 5 g/kg of diet for 4 weeks. Group IV received IM plus Spirulina for 4 weeks. Group V received IM for 2 weeks, followed by Spirulina for another 2 weeks. Group VI received spirulina for 2 weeks, followed by IM for another 2 weeks. Results revealed that IM significantly decreased body weight while increased feed conversion rate (FCR), total leukocytic count (TLC) and lymphocyte percent. Serum showed a decrease in haemagglutination inhibition (HI) antibody titer against newcastle disease (ND) vaccine. Antioxidant enzymes such as reduced glutathione (GSH) and catalase (CAT) significantly decreased; while malondialdehyde (MDA) increased in bursa of Fabricius tissue accompanied with histological changes. Administration of Spirulina in combination, before and after treatment with IM significantly ameliorated the IM-induced oxidative stress and immune damage due to its antioxidant properties.