Background: An understanding of atrial fibrillation (AF) mechanisms, as the most common cardiac arrhythmia, is essential for primary and secondary prevention. Some studies indicated an association between microalbuminuria and C-reactive protein (CRP) protein, with the incidence and prevalence of AF. This study aimed to investigate the relationship between permanent non-valvular AF with microalbuminuria and reactive protein C. Materials and Methods: In this case-control study, 40 permanent non-valvular AF patients and 40 non-AF patients (control group) were studied. Demographic data and measurements of albumin, urine creatinine, CRP, and microalbuminuria were recorded and compared between the two groups. Results: In patients with permanent non-valvular atrial fibrillation, CRP level (P<0.001) and microalbuminuria (P=0.012) were significantly higher than the control group. Also, in patients with permanent non-valvular AF, the CRP positive (P = 0.014) and microalbuminuria (P = 0.003) were significantly higher than controls. The results showed that elevated chance of permanent non-valvular AF with abnormal CRP was 4.25 (odds ratio [OR]= 4.25, 95% confidence interval [CI]: 1.18-1.28; P= 0.026), and with microalbuminuria was 6.54 (OR= 6.54, 95% CI: 1.65-25.89; P=0.007). Conclusion: An elevated CRP level and microalbuminuria were significantly associated with permanent non-valvular atrial fibrillation. A longitudinal study is necessary.[GMJ.2021;10:e2106] DOI:10.31661/gmj.v10i0.2106