Background: Adverse drug reactions (ADRs) are important causes of hospital admissions and inpatient complications. Renal dysfunction has a role in occurrence of ADRs. Aims: (1) To study the characteristics of ADRs among inpatients in Nephrology ward of a tertiary care hospital and (2) to compare these characteristics between patients with renal dysfunction and patients with normal renal function in same population of patients with ADRs. Materials And Methods : A retrospective study of inpatients with ADRs (July 2005-June 2006) in Nephrology ward of a tertiary care hospital. Statistical Analysis: ADR characteristics were analyzed using descriptive statistics. Comparisons were made between normal renal function group and renal dysfunction group by t-test and Chi-square test. Results: Of 1,464 case records, 244 (17%) patients were included. Two hundred sixty-seven drugs contributed to 294 ADRs. Serious ADRs accounted for 12% of the total ADRs. Renal/ electrolyte system (44%) was the most common organ system involved. Major clinical spectrum of ADRs included acute renal failure (22%), hypo/ hyperglycemia (13%), hyper/ hypokalemia (13%), bone marrow suppression (5%) and hepatic injuries (4%). Prednisolone (12%) was the most commonly implicated drug. Mean time to revert was 13