The current study was carried out to investigate the protective potential of Chlorella Vulgaris (CV) extract against sodium nitrite toxicity. Forty-five male Wister albino rats were assigned into 5 groups (n=9). Group (A) rats received normal saline orally for 3 months, Group (B): rats administered CV extract (70 mg/kg.BW) orally for 3 months, Group (C): rats received sodium nitrite (80 mg/kg.BW) orally for 3 months, Group (D): rats simultaneously received CV along with sodium nitrite treatment, orally, daily for 3 months, and Group (E): rats pre-treated with CV extract for 4 weeks followed by simultaneous treatment with sodium nitrite and CV extract for additional 8 weeks. Treatment of rats with sodium nitrite significantly increased serum urea and creatinine levels, associated with interstitial edema with mononuclear cells infiltrations, the renal tubular epithelium showed cloudy swelling and sever coagulative necrosis with desquamation of tubular epithelium and renal cast, the glomeruli showed congested glomerular capillaries. Besides, it decreased total leucocytic count and platelets count with normal hemoglobin, red blood cell count, hematocrit levels, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. Pre-treatment and co-treatment of sodium nitrite-treated rats with CV in groups (D & E) significantly prevented sodium nitrite-induced alterations of renal function and histological architecture. This study indicated that CV extract ameliorates the renal dysfunction induced by sodium nitrite toxicity.