Objective: To evaluate if elective single-blastocyst transfer (eSBT) could be adopted in women aged 36 or older? Design: Retrospective cohort study. Setting: Reproductive medicine center at a tertiary hospital. Population: Women aged ≥36 years received IVF ovarian stimulation cycles and had ≥ two blastocysts. Out of 429 women, 240 underwent eSBT and 189 double-blastocyst transfer (DBT) in the first transfer cycle. The subsequent frozen-thawed embryo transfer cycles were a combination of single- and double- blastocyst transfers. Methods: Analysis was stratified for patients in age groups 36-37, 38-39 and ≥40, taking into account the quality of the blastocyst transferred, as graded by morphological examination. Main outcomes measures: Cumulative livebirth rate (cLBR) from all transfers (fresh and frozen) accruing from a single oocyte retrieval. Results: The cLBR was 74.2% (178/240) versus 63.0% (119/189) after eSBT versus DBT, respectively (aOR: 1.09 (0.68, 1.75)). Time to live birth did not vary significantly between the two groups (HR: 0.85 (0.68,1.08)). The total number of children born was 194 after eSBT (162 singletons and 16 pairs of twins) versus 154 (84 singletons and 35 twins) pairs of after DBT. The odds ratios for preterm birth (<37 weeks’ gestation) (0.37 (0.21-0.64)), and low birthweight (<2.5 kg) (0.31 (0.16, 0.60)) were all lower in eSBT group than in DBT group. Conclusions: In women aged ≥36 years old with at least two blastocysts, cLBR following single- versus double- blastocyst transfer was comparable while the odds of multiple livebirths and adverse perinatal outcomes were reduced.