Purpose : To investigate blood flow velocity changes and resistivity index values of orbital vessels in Behcet disease with or without ocular involvement, in uveitis patients with different etiologies, and in healthy volunteers. Methods : Subjects were divided into four groups: those with ocular involvement in Behcet disease (group I), those without ocular involvement in Behcet disease (group II), uveitis patients with different etiologies (group III), and a control group (group IV). Twenty-seven eyes in group I, 14 eyes in group II, 25 eyes in group III, and 27 eyes in group IV were investigated. The blood flow in the central retinal artery (CRA), ophthalmic artery (OA), nasal posterior ciliary artery (NPCA), and the temporal posterior ciliary artery (TPCA) was measured using color Doppler ultrasonography (CDU) to determine the peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI). Results : The PSV and EDV value of CRA in groups I, II, and III were found to be significantly lower than those in the control group (p < 0.05 for each). Resistivity indexes of all arteries were higher in groups I, II, and III than the control group. The PSV and EDV in CRA, TPCA, and NPCA in Behcet disease patients with ocular involvement were significantly lower than all other groups ( p < 0.05). Conclusions: There are significant reductions in the blood flow values of the orbital arteries in patients with Behcet disease and uveitis patients with different etiologies when compared with healthy volunteers. The decrease in blood flow values in Behcet disease is more evident in patients with ocular involvement than the patients without ocular involvement. This might be the result of occlusive vasculitis, which is frequently seen in the retinal vessels of patients with Behcet disease.