Introduction: A standard assessment of embryo morphology at given time points does not always allow to transfer the embryo with the highest implantation potential. The effect of transfer of an improper embryo results in a lack of pregnancy or a miscarriage and, as a consequence, exposes the patient to unnecessary emotional stress and necessity to perform yet another transfer of frozen embryos. We present a case of a patient with earlier IVF failures. The use of time-lapse technique in this case helped to choose two good embryos. The transfer resulted in ongoing twin pregnancy. Material and methods: A 35-year-old woman with history of IVF-ET treatment failure was deemed eligible for an ICSI procedure because of the male factor. Ovarian stimulation was performed according to the agonist long protocol. Eight MII oocytes were fertilized and seven embryos were obtained. Continuous embryo monitoring was performed with the use of Primo Vision system. Forty-four hours after fertilization only 2 correctly developing embryos were identified. They were transferred on day 3. The development of the remaining 5 embryos was arrested. These embryos did not achieve the blastocyst stage on day 5-6 after fertilization. Forty days after embryo transfer, a twin pregnancy, confirmed with fetal heart rate of both fetuses, was revealed on ultrasound examination. Currently, the patient is at 27 weeks of ongoing twin gestation. Conclusions: The system of continuous embryo monitoring introduces new criteria for the examination of embryo development. These new parameters can be useful in clinical practice. However, prospective randomized studies are necessary to provide data confirming the usefulness of time-lapse technique in IVF treatment.