Recently, the role of vitamin D on autoimmune disorders has been investigated by several researchers. Hashimoto's thyroiditis (HT) chronic inflammation is one of autoimmune disorders, caused by environmental and genetic factors that may lead to produce antibodies from immune system that attacked thyroid gland, however; causes are not yet completely understood. Objective: To examine the 25 hydroxy vitamin D (25(OH) D3) status in Saudi Arabian females with HT Saudi female. Subjects and Methods: A cross-sectional study was recruited 50 female patients diagnosed by HT aged 20 and above, from King Abdulaziz University Hospital in Jeddah, Saudi Arabia. Patients were on specific routine of LT4 medication for a minimum 6 months. Blood samples were collected to measure the levels of 25(OH) D3, thyroid stimulation hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4) and calcium. Results: Biochemical data revealed that mean values for vitamin D among the three vitamin D categories were significant (P<0.05). There was insignificant relationship between vitamin D and TSH, as well as between vitamin D and FT3 (r=0.147, r=0.148, P>0.05) respectively. In addition, there was insignificant negative correlation between calcium level and TSH, and FT3 (r=-0.121, r=-0.264, P>0.05), respectively. Although there was a significant relationship between BMI categories and vitamin D levels, the study observed that majority of obese patients had high percentage of vitamin D deficiency. Conclusion: There was no association between 25(OH) D levels and HT among Saudi Arabian women. However, significant difference was found between vitamin D status in patients having insufficient and sufficient level (P < 0.05).