The pharmacokinetics of vancomycin vary significantly between specific groups of patients, such as critically ill patients and patients with hematological malignancy (HM) with febrile neutropenia (FN). Recent evidence suggests that the use of the usual standard dose of antibiotics in patients with FN may not offer adequate exposure due to pharmacokinetic variability (PK). Therefore, the purpose of this study is to assess the effect of FN on AUC0–24as a key parameter for vancomycin monitoring, as well as to determine which vancomycin PK parameters are affected by the presence of FN using Bayesian software PrecisePK in HM with FN. This study was carried out in King Abdulaziz Medical City. All adult patients who were admitted to the Princess Norah Oncology Center PNOC between 1 January and 2017 and 31 December 2020, hospitalized and received vancomycin with a steady-state trough concentration measured before the fourth dose, were included. During the trial period, 297 patients received vancomycin during their stay at the oncology center, 217 of them meeting the inclusion criteria. Pharmacokinetic parameters were estimated for the neutropenic and non-FN patients using the precise PK Bayesian platform. The result showed that there was a significant difference (p< 0.05) in vancomycin clearance Clvan, the volume of distribution at a steady-state Vdss, the volume of distribution for peripheral compartment Vdp, half-life for the elimination phase t½β, and the first-order rate constant for the elimination process β in FN compared to non-FN patients. Furthermore, AUC0–24was lower for FN patients compared to non-FN patients,p< 0.05. FN has a significant effect on the PK parameters of vancomycin and AUC0–24, which may require specific consideration during the treatment initiation.