Objective: This study was undertaken to report on the prevalence and management of late complications in twin-to-twin transfusion syndrome (TTTS) treated by laser therapy when both twins are alive 1 week after surgery. Study design: A total of 151 consecutive TTTS cases were treated by selective fetoscopic laser therapy. Cases in which both twins were alive 1 week after surgery were followed up with ultrasound and Doppler examination, including middle-cerebral artery peak systolic velocity measurement (MCA-PSV). Results: In the 151 cases treated with laser, both twins were still alive 7 days after the procedure in 101 cases. Intrauterine death of 1 and both twins occurred in 7 and 1 cases, respectively. Recurrence of TTTS with the polyhydramnios-oligohydramnios sequence occurred in 14 (14% ) cases. In another 13 (13% ) cases,amniotic fluid remained normal in both sacs, but MCA- PSV increased above 1.5 MoM in 1 twin and decreased concomitantly below 0.8 MoM in the co-twin. This was related to anemia and polycythemia, respectively, and resulted from unidirectional feto-fetal blood transfusion, mainly from former recipients into former donors. Late complications were managed accordingly by repeat laser, amnioreduction, cord coagulation, intrauterine blood transfusion, or elective delivery. Conclusion: MCA-PSV Doppler measurements are useful in the follow-up of double survivors to detect and manage late complications after selective laser therapy. Objective: This study was undertaken to report on the prevalence and management of late complications in twin-to-twin transfusion syndrome (TTTS) treated by laser therapy when both twins are alive 1 week after surgery. Study design: A total of 151 consecutive TTTS cases were treated by selective fetoscopic laser therapy. Cases in which both twins were alive 1 week after surgery were followed up with ultrasound and Doppler examination, including middle-cerebral artery peak systolic velocity measurement (MCA-PSV). Results: In the 151 cases treated with laser, both twins were still alive for 7 days after the procedure in 101 cases. Intrauterine death of 1 and both twins occurred in 7 and 1 cases, respectively. Recurrence of TTTS with the polyhydramnios-oligohydramnios sequence occurred in 14 (14%) In another 13 (13%) cases, amniotic fluid remained normal in both sacs, but MCA-PSV increased above 1.5 MoM in 1 twin and decreased concomitantly below 0.8 MoM in the co-twin. This was rela ted to anemia and polycythemia, respectively, and resulted from unidirectional feto-fetal blood transfusion, mainly from former recipients into former donors. MCA-PSV Doppler measurements are useful in the follow-up of double survivors to detect and manage late complications after selective laser therapy.