Methods: Data on 209 twin pregnancies and 418 neonates who were delivered in the tertiary center between 2003 and 2009 were retrospectively reviewed. Perinatal and neonatal outcomes were compared between twins from monochorionic and dichorionic pregnancies. Results: We were able to establish chorionicity in 148 out of 209 twin pregnancies, and only these have been recruited in this study. Monochorionic pregnancies (n = 56; 38%) in comparison with dichorionic (n = 92; 62%) were related to a higher risk of preterm birth (both between 33–36 hbd and below 33 hbd; P < 0.01), low and very low birth weight (P = 0.012), Apgar scores between 1–4 (P = 0.029). Monochorionic twins were more often admitted to neonatal intensive care unit (58% vs. 41%; P = 0.006) and had a higher incidence of intraventricular hemorrhage (39% vs. 20%; P < 0.001), anemia (31% vs. 14%; P < 0.001), sepsis (10% vs. 2%; P < 0.001) and metabolic complications (14% vs. 7.6%; P < 0.02). Both groups did not differ in the rate of neonatal death (7.1% vs. 4.3%, NS) and neonatal pneumonia (35% vs. 26%, NS). Exclusion of 10 (18%) pairs of twins with TTTS did not affect the results. Conclusions: Monochorionicity is a risk factor in twin pregnancy. It is associated with a higher risk of prematurity, worse neonatal condition at birth and during the first month of life and longer hospitalization but it is not related to a higher neonatal mortality.