© 2021 Elsevier Masson SASObjective: To compare the efficacy of follicular flushing (FF) with double lumen needle and direct follicular aspiration with single lumen needle in terms of oocyte yield in mono-follicular responder patients undergoing assisted reproduction techniques (ART). Materials and Methods: Prospective ‘quasi-experimental’ study was carried out in an IVF center. Infertile women 18–42 years of age with diminished ovarian reserve who revealed a single follicle >17 mm on the day of oocyte retrieval were included in the study. Follicular flushing up to 8 times was performed in FF group using an 17-G double lumen needle. Direct follicular aspiration using a 17-G single lumen needle without FF was performed in direct aspiration group. Total numbers of collected oocytes, metaphase 2 oocytes, fertilization and pregnancy rates were compared among groups. Results: A total of 206 women underwent oocyte retrieval procedure; 106 women were assigned to FF and 100 women into direct aspiration arm. Overall oocyte retrieval rate was 50.4% in all cases. The total oocyte retrieval rate was higher (65/106, 61.9%) in FF group, than in direct aspiration group (39/100, 39%, p = 0.001). Metaphase 2 oocyte rate was also higher in FF group (47/106, 44.3% vs 29/100, 29% p = 0.04). Fertilization rates, total number of patients with a cleavage stage embryo and grade 1 cleavage embryo were similar among the groups (p>0.5). Numbers of positive hCG, ongoing pregnancy and miscarriage rates were similar among groups. Conclusion: Follicular flushing using double lumen needle in mono-follicular responder patients with diminished ovarian reserve yields more oocytes and mature oocytes than direct aspiration of follicles.