Introduction Chronic Kidney Disease (CKD) is being recognized as a global public health problem. CKD is a major non-communicable disease with the global prevalence varying between 10.5% and 13.1%. Diabetes and hypertension appear to be the leading causes of CKD and End Stage Renal Disease worldwide. The aim of this study is to determine the prevalence of CKD and its associated factors among patients admitted to medical ward in a tertiary hospital, Northern Ethiopia. Methodology: An institution based cross-sectional study was undertaken using systematic random sampling technique to select study participants. Sample sizes of 450 patients were included in the study. Data was collected using a pre-tested semi-structured questionnaire designed to meet the study objective. The data collection period was from October 20, 2017 to March 20, 2018 G.C. Data was analyzed using SPSS version 21.The odds ratio with their 95% confidence interval and P value were calculated. Statistical significance was declared if P value < 0.05. Result: Of the 450 patients, 260(57.8%) were males. More than half (54.2%) were between ages of 25 to 40 years. The overall prevalence of CKD among patients admitted to medical ward was 17.3% (95% CI 13 - 29.9) and 14.4% (95 % CI 6.2 – 12.3) by Cockcroft Gault and MDRD equations respectively. Prevalence of stage 5 CKD was 61.5% by Cockcroft Gault equation. Hypertension AOR 3(95%CI 1.28, 4.1), history of recurrent urinary tract infection AOR 3.5 (95% CI 1.1, 7.3) and history of using nephrotoxic drugs AOR 3.4 (95% CI 2, 9.3) were significantly associated with CKD.  Conclusion: The prevalence of CKD among adult patients admitted to medical ward in tertiary hospital, Northern Ethiopia was high and majority of patients with CKD were stage 5. Hypertension, use of nephrotoxic agents and recurrent urinary tract infections were significantly associated with CKD.