Abstract : Atrial fibrillation is the commonest type of arrhythmias with significant mortality and morbidities. There is a correlation between AF and renal impairment and this correlation is complex and may be a manifestation of cardiorenal syndrome, a bidirectional complication of these diseases or its treatment or both coexist in same disease. To evaluate frequency of renal indices abnormality among patients with atrial fibrillation. By using cross sectional descriptive study, randomly selected 52 atrial fibrillation patients admitted to Coronary care unit in Al-Nasiriya city underwent a complete evaluation for renal indices including blood urea, serum creatinine, urinalysis, serum electrolytes, Albumin creatinine ratio and ultrasound for renal system. Also performed questionnaire were obtained from all patients. Patients labeled as chronic kidney disease or underwent to renal replacement therapy were excluded. Mean age of patient’s 59.6±13.1 years and for Age at diagnosis 56.9±14.9. All patients have one or more abnormal renal indices. Most abnormalities appear in urinalysis (100% of patients) followed by abnormal Albumin creatinine ratio (48% of patients), Blood urea in 26.92%, Serum creatinine in 9.6% and ultrasound in 7.69%. 75% had chronic diseases plus AF. Significant correlation between male gender and highly abnormal blood urea (P.value=0.05), serum creatinine (P.value=0.014) and Albumin creatinine ratio (P.value=0.013). Also between direct cardioversion shock and blood urea (P.value=0.018), serum creatinine (P.value=0.006) and Albumin creatinine ratio (P.value=0.047). Blood urea correlated with abnormal echo finding (P.value=0.02) and number of medications that used for atrial fibrillation management (P.value=0.031). Some renal indices is abnormal in Atrial fibrillation patients especially urinalysis, blood urea, serum creatinine and Albumin creatinine ratio. In addition, this abnormality related to gender, using of direct cardioversion shock, echo abnormalities and number of medications for atrial fibrillation.