The long‐term use of subcutaneous implanted ports for chemotherapy in cancer patients has been associated with the occurrence of thrombosis and infection. In this study, we compared the safety and efficacy of administration of 1000 U of heparin flushes in prolonged interval (every 6 weeks) with standard dose and schedule (500 U every 4 weeks) for port‐related infections and thrombosis during periods of non‐use. Data were collected retrospectively from patients treated for various cancer types (matched as 2:1 for age, gender, stage of the disease). Patients who had diseases that could cause thrombosis or bleeding in their past medical history, or were taking oral anticoagulants, or had contraindications for heparin usage were excluded. After completing their chemotherapy, 59 patients received prolonged interval, while 30 patients received standard schedule. All patients were followed for at least 1 year. No clinically documented port‐related infection or thrombosis has been found in both groups. Also, none of the devices was removed during this time. Prophylactic flushing of central venous ports with 1000 U of heparin in every 6 weeks might be a safe, easy, cheaper, comfortable and effective alternative to standard dose and schedule for preventing thrombosis and infections.