OBJECTIVE: To evaluate the efficacy and safety of adjuvant chemotherapy of three steps (ACTS) in patients newly diagnosed with advanced ovarian cancer. DESIGN: Randomised clinical trial. SETTING: The study was conducted at a single centre. POPULATION: Newly diagnosed patients with advanced ovarian cancer who showed a complete response to standard chemotherapy (paclitaxel plus carboplatin) were included in this study. METHODS: In this open-label phase II trial, patients were randomised 1:1 to receive either ACTS therapy or no maintenance treatment. The ACTS group received step-2 chemotherapy with cyclophosphamide and etoposide (six cycles) and step-3 chemotherapy with cyclophosphamide and carboplatin (six cycles). Key endpoints were overall survival (OS), progression-free survival (PFS) and adverse events. MAIN OUTCOME MEASURES: The main outcome measures were OS, PFS and adverse events. RESULTS: Of the 130 enrolled patients, 65 were assigned to the ACTS group and 65 to the control group. The median OS in the ACTS group was 61.2 months, and patients in the ACTS group had a significantly longer PFS than those in the control group (22.2 vs. 9.73 months). The most common grade ≥ 3 adverse events were thrombocytopenia and neutropenia. No treatment-related deaths occurred during the study period. CONCLUSIONS: The Maintenance ACTS Regimen Improved PFS but Not OS and Showed a Tolerable Safety Profile in Patients Newly Diagnosed With Advanced Ovarian cancer. TRIAL REGISTRATION: ClinicalTrials.org NCT02562365.