Background: Diclofenac sodium is associated with adverse effects, including hypertension, hepatotoxicity, renal damage, increased cardiovascular risk, and gastrointestinal toxicity. Selenium is a vital trace mineral contributes significantly to protecting against oxidative damage. Objectives: The present study was desinged to evaluate affects of diclofenac sodium on immunological, hematological, and micronutrient status Evaluate the potential préventive impact of selenium when given concurrently with it. Methods: Twenty albino fernale rats, with weights ranging from 170-200 grams were selected at random assigned. to four groups, each with five rats. Untreated (1 mi distilled water for 21 days), selenium cohort (0.25 mg/kg for 21 days), diclofenac sodium cohort (10 mg/kg for 14 days), and protective cohort (selenium + diclofenac sodium). Where received selenium for seven days followed by selenium and diclofenac sodium two hours apart over two weeks. Results Treatment with diclofenac sodium led to a significant reduction in the count of RBC, Hb, HCT concentrations, and levels of vitamin D, zinc, Ca, Mg, C3. Conversely, it resulted in a notable rise in WBCs count, neutrophil percentage, levels of C4 and IgA. This work concluded that selenium supplementation reduced oxidative stress, inflammation which caused by diclofenac sodium in treated female rats.