The reference values of hematological markers currently used in Sudan have been obtained from researches on populations in developed countries and may not be applicable in Sudan. It has previously been shown that the normal hemoglobin level in Sudanese children is different from international values. The objectives of this study were to establish the reference ranges of white blood cells and differential count in healthy Sudanese adults. The present study included 1076 healthy Sudanese adults from both sexes and five states, with age range of 20 – 60 years. Clinical examination was performed, weight and height were measured, and BMI was calculated. Blood samples were obtained from brachial veins and drawn in EDTA tubes. WBCs and differential count were analyzed using Sysmex KX-21 automated hematology analyzer. SPSS version 25 statistical software was used for data analysis, P value < 0.05 was considered significant and 95% CI was accepted. The mean age of participants was 25.23±9.64 years. The median of WBCs count was 5×103/µL with reference range of (2.9-9.6× 103/µL). Neutrophils count was 2.3(1.7-3.1× 103/µL), while lymphocytes was 2.1(1.8-2.5× 103/µL). The median of WBCs was significantly higher in female [5.1 × 103/µL (range: 4.2- 6.3× 103/µL)] than male [5.0× 103 /µL (range: 4.0- 6.0× 103/µL)] (p <0.05). Our results showed that WBCs count was positively correlated with BMI. The count was found to be significantly higher in Red sea and Darfur states compared with the other states. The reference ranges of WBCs count in Sudanese are lower than the international one and should be used in Sudan