Women with premenstrual syndrome (PMS) are at increased risk for depression throughout their lives. White matter (WM) microstructure and inflammatory cytokine alterations have been proposed in its etiology. To investigate whether WM, assessed using diffusion tensor imaging (DTI), and inflammatory cytokine levels are altered in PMS, and to examine the relationships between WM microstructure, inflammatory cytokines, and symptom severity. Prospective. Forty-two PMS patients and 58 healthy controls (HCs), categorized according to the daily record of severity of problems (DRSP). 3-T, echo planar imaging DTI. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were measured by using tract-based spatial statistics (TBSS). Venous blood was collected to measure cytokines, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Symptoms were assessed by using the DRSP. Two-sample t test or Mann-Whitney U test were used to compare the DRSP and cytokines. Abnormal DTI metrics in WM were extracted and the differences between groups were analyzed by using two sample t-tests. Spearman's correlation (r) was used to assess the relationship between DTI metrics, cytokines, and DRSP. A P-value <0.05 with FDR correction was considered statistically significant. Compared with HCs, PMS patients showed significantly lower FA in the corpus callosum and corona radiata, and significantly higher MD, AD, and RD in the corticospinal tract (CST), and significantly higher MD and RD in the anterior thalamic radiation (ATR). These differential metrics were significantly correlated with DRSP. Patients showed significantly higher IL-1β and TNF-α than HCs. Moreover, TNF-α correlated positively with MD, AD, and RD in both groups (r range, 0.256-0.315). Alterations of WM microstructure and IL-1β and TNF-α may be associated with PMS symptom severity, and TNF-α may correlate with DTI metrics of CST and ATR pathways. 1 TECHNICAL EFFICACY: Stage 2.