Objective: our aim is, to establish the prevalence of vitamin D deficiency inpatients with SLE and its relation to various clinical and laboratory variables of thediseaseMethods: Our study included 30 female SLE paents fulfilling ACR criteria for theclassification of SLE and 20 age and sex matched healthy control group. Full clinicalexamination and routine labs were done to the patients. Serum 25(OH)D wasestimated using human (EIA) enzyme immunoassay. We measured the serum level of25(OH)D in paents and controls. According to the 25(OH)D level we classified ourpaents into 3 groups, group of normal vitamin D level [>30 ng/ml], group ofinsufficient vitamin D level [12‐30 ng/ml] and a group of deficient vitamin d level [<12ng/ml]. SLE activity was measured by SLEDAI‐2K and irreversible organ damage by theSLICC index. Fague was quanfied using a 0–10 visual analogue scale (VAS).Results: We found high statistical significant difference in the serum 25(OH)Dlevel in SLE patients versus controls [28.8±26 vs. 97±47 (P<0.001)]. 13 (43.3%) and 8(26.7%) paents presented with vitamin D insufficiency and deficiency, respecvely.Statistical significant differences were detected on comparing the 3 SLE groups asregard serum Ca [P<0.001], and creatinine level [P=0.048]. The serum Ca was lower inthe group of deficient and insufficient 25(OH)D levels compared to the group of normal25(OH)D level, while the serum creanine was high in the group of normal 25(OH)Dlevel compared to the other groups. A high statistically significant difference amongthe 3 SLE groups [P<0.001], was detected as regard the presence of haematologicparameters. Also, a statistical significant difference among the 3 SLE groups, [P<0.005]was detected as regard the presence of skin rash in general and malar rash inparticular.Conclusion: low 25(OH)D level was detected among SLE patients more than thehealthy population. There was significant associaon between the 25(OH)D level, andskin rash, haematologic manifestations, calcium and creatinine levels.