Aims <p>To evaluate the prognostic role of serum albumin level in the radiological progression of gonarthrosis.</p> Methods <p>Two hundered and fifty patients with gonarthrosis (Group1: early stage gonarthrosis, Group 2: late-stage gonarthrosis), and 125 patients as a control group (Group 3) were included in this retrospective cross-sectional study. Age, gender, the Kellgren-Lawrence (KL) stage, serum albumin level, C-reactive protein (CRP)/albumin, platelet/lymphocyte, neutrophil/lymphocyte, lymphocyte/monocyte, lymphocyte/CRP, The Aggregate Index of Systemic Inflammation, Systemic Inflammatory Response Index, Systemic Immune Inflammation Index, Prognostic Nutritional Index (PNI), Modified Systemic Inflammation Score (mSIS) were recorded.</p> Results <p>Albumin and PNI were lower compared to the Group 3 in the Group 1 and Group 2, and compared to the Group 1 in the Group 2 (for all <i>p</i> ≤ 0.001). mSIS was higher in the Group 1 and Group 2 compared to the Group 3 (<i>p</i> &lt; 0.001 for both), and in the Group 2 compared to the Group 1 (<i>p</i> = 0.01). CRP/albumin was higher in Group 2 compared to Group 1 (<i>p</i> = 0.004). KL stage was moderately negatively correlated with albumin (<i>r</i> = −0.45 <i>p</i> &lt; 0,001) and PNI (<i>r</i> = −0.40 <i>p</i> &lt; 0.001). Albumin and PNI values ​have diagnostic value in predicting early-stage (the cut-off value for albumin: 40.05&#xa0;g/L, for PNI: 52.28) and late-stage (the cut-off value for albumin: 39.35&#xa0;g/L, for PNI: 51.03) gonarthrosis in patients without gonarthrosis and late-stage gonarthrosis in patients with early-stage gonarthrosis (the cut-off value for albumin level: 38.55&#xa0;g/L, for PNI: 49.73).</p> Conclusions <p>Serum albumin level has a prognostic role in the radiological progression of gonarthrosis.</p>