Background: Red cell distribution width (RDW) is a measurement of the degree of anisocytosis,rnor the degree of red cell size variability present in a blood sample. RDW has been reported as arnsignificant diagnostic as well as prognostic lab marker for many non-hematological disorders. Arnstudy conducted in Addis Ababa showed that RDW was one of the less recognized andrnunderutilized laboratory marker in clinical practice.rnObjective: To describe the clinical utility of RDW in the investigation of non hematologicalrndisorders at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.rnMethods: A Case-control and questionnaire based study was conducted at Tikur AnbessarnSpecialized Hospital, Addis Ababa, Ethiopia. A convenient sampling technique was employedrnand a total sample size of 150 ( 100 cases and 50 apparently healthy controls) and 100 cliniciansrnnon hematological diseases yet failed to utilize it. Reason behind it is yet to be identified but thernhabit of utilizing RDW in the investigation of diseases other than anemia should be urged andrnencouraged.rnKey words: RDW, clinical utility, non-hematological diseasernrnwere included from May to August, 2015. Cases were adult patients diagnosed with heart, liverrnand kidney diseases. RDW was determined using Sysmex XT-2000i Automated HematologyrnAnalyzer. The data were entered in to Excel spread sheet and imported for analysis to SPSSrnversion 19 software (SPSS INC, Chicago, IL, USA). Frequency, mean distribution, paired t testrnand chi square was calculated P values less than 0.05 were considered statistically significant.rnResult: Half of the clinicians had the Knowledge that elevated RDW could be an indication ofrnnon hematological diseases. However, 68% (68/100) of them rated that they rarely or never usernRDW in the investigation or follow up of patients having non hematological diseases. Paired trntest revealed mean difference of 2.53Â± 4.3 existed between the cases and control groups with arnconfidence interval of 1.314-3.76 (p