Purpose: Even in the absence of extravasation, some patients develop induration at the peripheral intravenous catheterization site prior to the next day's treatment. Infusion site induration commonly affects patients who undergo repeated chemotherapy administrations. Vessel health is crucial for the continuation of chemotherapy. However, there is no effective method to prevent induration. Hence, this study aimed to investigate the factors that could cause induration for preventing its occurrence. Methods: This study was a secondary analysis of a prospective observational study. All participants were undergoing outpatient chemotherapy. Participant characteristics and related catheterization data were collected on the treatment day as baseline, and induration incidence was recorded on the subsequent treatment day. Receiver operating characteristic (ROC) analysis was performed to determine the sensitivity and specificity of cutoff points of the vein and catheter diameter ratios for distinguishing between developed induration and not developed induration. Additionally, cox regression analysis with multiple imputation was used to investigate the factors that predicted induration. Results: Seventy-one patients participated in the study. The cutoff point of the vein/catheter diameter ratio calculated using ROC analysis was ≥3.7. The ratio of larger-diameter veins to catheter diameter of ≥3.7 times was negatively associated with induration in both complete case analysis (HR: 0.11; p = 0.034) and multiple imputation analysis (HR: 0.12; p = .049). Conclusions Selecting the vein with 3.7 times higher diameter than the catheter diameter for the catheterization site may help prevent induration on the next treatment day.