Tania Siahanidou completed her studies at the Medical School of Athens University in 1984. Specialized in Pediatrics in the Second Pediatric Department of "P. & A. Kyriakou" Children's Hospital. She worked as a Consultant at NHS, "Aghia Sophia" Children’s Hospital, Neonatal Unit of the First Department of Pediatrics of Athens University (1997-2006). Appointed Lecturer in Pediatrics-Neonatology, Athens University, Medical School (2006) and then Assistant Professor in Pediatrics-Neonatology (2011) in the First Department of Pediatrics of Athens University, “Aghia Sophia” Children's Hospital, where she works until today. She was trained in Neonatology-Neonatal Gastroenterology &Nutrition at the Neonatal Intensive Care Unit of "St George's" Hospial, London, UK (2002).

Since September 2009, was appointed Head of the Neonatal Unit of the First Department of Pediatrics, Athens University. The Neonatal Unit of the First Department of Pediatrics is a Special Care Unit (Level II) of 30 neonatal beds providing care to approximately 600 preterm and full-term neonates with various diseases each year. She was elected secretary (2009-2011) and board member (2011-2013) of the Greek Association of Perinatal Medicine, member of working group for Neonatology (2005-2009) and member of the scientific committee of the Greek Association of Perinatal Medicine (2009-2011), as well as member of the committee of Hellenic Ministry of Health & Welfare for determining the cost of hospitalization for neonates (2011). Her research projects involve Pediatrics, and mostly Neonatology, with focus on feeding & nutrition of neonates, study of peptides and hormones involved in metabolism, but also on various other topics including neonatal infections, oxidative stress, thyroid function of preterm infants and neurodevelopment/motor development of newborns. She has published over 35 papers in international journals and 55 papers in Greek journals after crisis.