Chronic Kidney Disease (CKD) is considered one of the major health problems affecting kidney function progressively. It is characterized by a continuous decline in the kidneys' ability to filter blood and eliminate waste products and toxic substances. In advanced stages, it may lead to kidney failure, requiring dialysis or kidney transplantation. Gene expression is an important field in understanding the molecular mechanisms associated with the progression of chronic kidney disease. It refers to the process by which genetic information stored in DNA is used to produce RNA molecules and proteins that perform essential biological functions within cells. Changes in gene expression levels may disrupt kidney cell functions and contribute to disease progression. Molecular studies have shown that several genes are associated with the pathological processes involved in chronic kidney disease, including genes responsible for inflammation, oxidative stress, and renal fibrosis. Transforming Growth Factor-Beta (TGF-β) is considered one of the most important factors involved in activating fibrotic pathways, as it contributes to increased deposition of extracellular matrix components, leading to kidney tissue damage and the gradual loss of normal kidney function. Furthermore, abnormal expression of genes associated with inflammatory responses, such as IL-6 and TNF-α, may increase inflammatory activity within kidney tissues, potentially accelerating renal damage. In addition, changes in the expression of genes regulating oxidative stress may disrupt the balance between free radicals and antioxidants, increasing the likelihood of cellular damage. The importance of studying gene expression lies in its potential use as a biomarker for understanding disease progression and identifying molecular changes occurring at different stages. Molecular biology techniques, such as Quantitative Real-Time Polymerase Chain Reaction (Real-Time PCR), allow researchers to measure gene expression levels and monitor changes in the activity of genes associated with kidney function. In conclusion, gene expression represents a fundamental aspect of understanding chronic kidney disease at the molecular level. Studying gene expression may contribute to discovering new biomarkers for early diagnosis, evaluating disease progression, and opening new possibilities for developing therapeutic approaches targeting the molecular pathways responsible for kidney tissue damage. Al-Mustaqbal University – The First University in Iraq