Purpose@#Totally implantable venous access ports (TIVAPs) can be used long-term for safe administration of intravenous drugs. TIVAP complications include catheter-related infections, venous thrombosis, extravasation, TIVAP migration, and pain. The relationship between the timing of the first chemotherapy administration after port implantation and complications is controversial. This study aimed to investigate the safety of immediate use of TIVAPs and the associated risk factors for complications. @*Methods@#Between January 2016 and December 2018, 305 patients (median age, 53 years; 256 women) who underwent TIVAP placement at our institution were included. Chemotherapy was administered within 2 days of implantation. A retrospective analysis of patients’ clinical data was performed to investigate catheter days and complications of TIVAPs. @*Results@#Overall, 305 patients were evaluated over 57,324 catheter days (median, 168 catheter days; interquartile range, 105). The median interval between placement and first use of TIVAPs was 0.98 days. The overall morbidity rate was 2.95%. Nine complications occurred in nine patients, including TIVAP-related infection (4), pain (2), port occlusion (1), thrombosis (1), and scar disunion (1), of which five required port removal (1.64%). The median number of catheter days before complications occurred was 61 (range, 10–457 days; interquartile range, 51). No complications occurred within 7 days of implantation. Body mass index was an independent risk factor for TIVAP-related complications in the Cox proportional hazards model (multivariable analysis: hazard ratio, 1.221; 95% confidence interval, 1.054–1.414; P = 0.008). @*Conclusion@#This study suggests the safe long-term use of TIVAPs following their immediate chemotherapy administration within 2 days of implantation.