Background: Sodium nitrite is an inorganic compound with the chemical formula NaNO₂. It is probably best known as a food additive to prevent botulism. Aim of the work: The current study was designed to investigate the possible protective effect of aqueous extract of Lipidium sativum seeds on hematotoxicity induced by sodium nitrite (NaNO₂) in male albino rats. Materials and Methods: The experimental animals were divided into four groups. The first group without any treatment and served as control. The second group was given an intraperitoneal injection (IP) of a single dose of sodium nitrite (50 mg/kg body weight) 24 h prior to decapitation.The third group was received orally 300 mg/kg body weight of Lipidium sativum seeds extract for four weeks. The fourth group were treated orally with Lipidium sativum seeds extract (300 mg/kg body weight) for four weeks, prior to IP injection with a single dose of sodium nitrite (50 mg/kg body weight). Finally, blood samples were collected for hematological parameters estimation including red blood cell count (RBCs), hemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count (PLTs) and total and differential white blood cells (WBCs). Results: The obtained data revealed that NaNO₂ induced a significant decrease in the percentages of RBCs count, Hb content, PCV, MCH, MCHC, platelets, WBCs, neutrophils, monocytes, eosinophils and basophils count. On the other hand, a noticeable increase in the percentage of lymphocytes was recorded in NaNO₂ treated rats. Whereas, the treatment with Lipidium sativum seeds extract alone to rats did not cause a significant alterations in the hematological indices comparing to control group. There was a significant increase in total WBCs and neutrophils counts and a significant decrease in lymphocyts, monocyts, eosinophils and basophils counts. The treatment with Lipidium sativum seeds extract before injection with sodium nitrite were significantly ameliorated the changes induced in hematological parameters which caused by sodium nitrite comparing with the control group. Whereas, there were a significant increase in total WBCs count, neutrophils and eosinophils and a significant decrease in lymphocytes, monocytes and basophils. Conclusion: It could be concluded that the treatment with Lipidium sativum seeds extract significantly improved the changes in hematological parameters that caused by sodium nitrite and induced a significant increase of WBCs count may stimulate the animal's immune system activation.