Twin pregnancy is assumed to increase the risk of maternal and neonatal complications. This situation is worse in Sub-Saharan Africa because of lack of well-equipped facilities. Studies on twin pregnancy and maternal complications are limited in Ethiopia. Thus, this study aimed to fill this gap. A hospital-based cohort study was conducted in Jimma University Specialized Hospital on 144 twin deliveries and 288 singleton deliveries. Data were collected through face-to-face interview by using structured-questionnaire and analysed by SPSS V.20.0. The relative risks of twin deliveries were significantly higher for the occurrence of hypertension, preterm labor, poor progress of labor, premature rupture of membrane, polyhydramnos, cord prolapse, uterine atony, postpartum haemorrhage, puerperal sepsis and maternal death as compared with singleton deliveries. In conclusion, women with twin pregnancy were at a higher risk of medical and obstetric complications during antepartum, intrapartum and postpartum periods. Thus, special emphasis should be given to mothers with twin pregnancies during antenatal care, delivery and postnatal care so as to prevent or manage the complications earlier.