Objective To investigate the changes of dynorphin A (DYN‑A) in plasma and derived from peripheral white blood cells (WBCs) of diabetic patients during the perioperative period. Methods Patients scheduled for posterior lumbar interbody fusion (PLIF) under general anesthesia were selected and divided into two groups: a non‑diabetes group (an NDM group, n=49) and a diabetes group (a DM group, n=23). The total number of peripheral WBCs and their classification such as lymphocytes, monocytes, and granulocytes were counted before and after operation. Before anesthesia (T1), and after awakening from anesthesia (T2), blood samples from the non‑infusion sided elbow vein were collected. The plasma levels of DYN‑A were measured by enzyme‑linked immunosorbent assay (ELISA). Flow cytometry (FCM) was used to determine the percentage of DYN‑A fluorescence positive cells and mean fluorescence intensity (MFI) of WBCs. Results In the NDM group, the total number of peripheral WBCs at T2 ［(12.9±4.1)×109/L］ was remarkably higher than the count at T1 ［(6.3±1.6)×109/L］(P<0.05). The granulocyte count at T2［(10.7±4.0)×109/L］was higher than the count at T1 ［(3.7±1.3)×109/L］(P<0.05). The monocyte count at T2［(0.66±0.30)×109/L］ was higher than the count at T1 ［(0.46±0.15)×109/L］(P<0.05). The lymphocyte count at T2 ［(1.2±0.5)×109/L］ was lower than the count at T1 ［(2.0±0.7)×109/L］(P<0.05). In the DM group, the total number of peripheral WBCs at T2 ［(11.7±3.5)×109/L］was also higher than that at T1 ［(6.8±2.1)×109/L］(P<0.05). The granulocyte count at T2 ［(9.6±3.9)×109/L］ was higher than that at T1 ［(4.1±2.1)×109/L］(P<0.05). The lymphocyte count at T2 ［(1.1±0.4)×109/L］ was significantly lower than the count at T1 ［(1.8±0.6)×109/L］(P<0.05). Also, the monocyte count at T2 increased. The level of plasma DYN‑A significantly decreased in the NDM and DM groups at T2, compared with that at T1 (P<0.05). Compared with the NDM group, the percentage of each type of WBCs with fluorescent positive DYN‑A significantly increased at T1 in the DM group (P<0.05). Compared with those at T1, the percentage of each type of WBCs with fluorescent positive DYN‑A remarkably reduced at T2 in the DM group (P<0.05). But there was no significant change in the NDM group after operation. Compared with those at T1, the MFI of DYN‑A in granulocytes reduced at T2 in the NDM group (P<0.05), while the DM group showed decreases in the MFI of DYN‑A at T2 (P>0.05). Conclusions The total number of peripheral WBCs significantly increases in the diabetic patients during the perioperative period, with the most obvious increase in granulocyte count. The percentage of DYN‑A positive cells in leukocyte classification significantly decreases, while the level of DYN‑A in plasma and derived from granulocytes also decreases. These changes are related to the perioperative stress and immune status of the diabetic patients.