The paper presents current views and recommendations for pregnancy complicated by TTTS. The symptoms that should attract our attention during the first-trimester ultrasound, i.e. CRL asymmetry NT > 95th percentile, or 20% or more of the NT difference between the fetuses, absent or reversed A wave in DV, and TV regurgitation, are discussed and presented. Similarly symptoms that should attract our attention in the second trimester such as amniotic fluid volume imbalance, asymmetry in the size of the urinary bladders, abdominal circumferences discordance, inter-twin membrane folding, membranous attachment of the donor's umbilical cord, different placental echogenicity and abnormal Doppler measurements, are listed. The paper presents the principle of monitoring based on ultrasound examination, including Doppler studies. The necessity and usefulness of echocardiography is underlined. It is also stressed that the frequency of monitoring depends on the severity of hemodynamic changes and the check-up rate varies from once a week to daily monitoring in extreme cases. This paper presents a variety of therapeutic options, including conservative management, septostomy amnioreduction, laser and selective fetoreduction. Taking into account the level of disease severity stages I and V can be managed conservatively. Fetoscopic laser coagulation of anastomoses, which can be used almost in all stages of TTTS (I-IV), remains to be the treatment of choice. However the current level of evidence does not yet allow us to determine whether laser coagulation increases or reduces the risk of neurodevelopmental delay and mental retardation in children, as compared to other types of therapy. Amnioreduction may be recommended in cases when laser therapy is unavailable or as first-line therapy before transporting the patient to the intrauterine therapy center.