Background: About 70% of medical decisions made by physicians are based on the informationrnpresented by laboratory results. However, test results by themselves are valueless unless reportedrnwith the appropriate reference interval or medical decision limit. Currently, Ethiopia use referencernintervals adopted from textbooks that refer mainly to Caucasian subjects. The country havingrnheterogeneous population, there is a need to establish locally derived hematological referencerninterval that could be used in Asella town, Arsi zone, Ethiopia. rn Objective: To establish hematological reference intervals for apparently healthy adults in Asellarntown, southeast, Ethiopia. rnMethods: A cross sectional study was conducted from January to March 2019 on apparentlyrnhealthy individuals in Asella town aged from 18-60 years. Predesigned and structuredrnquestionnaire was used for collection of data on socio-demographic characteristics and dietaryrnpattern of the reference population. Systematic random sampling technique was used. About 3mlrnof EDTA whole blood was collected and analyzed using Sysmex KX 21N automated hematologyrnanalyzer which analyses 60 tests per hour. The data was entered and analyzed by appropriaternstatistical software (Epi Info and SPSS) and interpreted using non-parametric methods, by whichrncentral 95% of the measured values was included in the intervals. rnResult: a total of 494 participants were recruited and 424 participants were involved in this studyrnwith the median age of 28 years. Except WBC (3.4 to 10.1 x10rn9rn/L) which showed no significantrndifference, other men and non-pregnant women reference intervals are: RBC (4.77 to 6.07 x10rn/L;rn4.18 to 5.29 x10rn12rn/L), HGB (14.7 to 18.1 gm/dL; 12.7 to 15.7gm/dL), HCT (42.1 to 51.3%; 37.1rnto 44.4%) and PLT (159 to 336 x10rn9rn/L; 177 to 376 x10rn9rn/L), respectively. Pregnant womenâ€™s WBC,rnRBC, HGB and PLT are (4.9 to 13.2 x10rn9rn/L, 3.58 to 4.9 x10rn12rn/L, 11.0 to 14.6gm/dL and (138 torn368 x10rn9rn/L), respectively. rnConclusion: most of the hematological RI of this study was significantly different from currentlyrnin use in Asella referral and teaching hospital laboratory. The difference was also observed inrnstudies of other African countries as well as studies from different parts of Ethiopia. rn12