Marián Duffek completed his studies at the Faculty of Medicine of P.J. Štefánik University in Košice, department of general medicine. He obtained a 1st-degree certificate in surgery from the Slovak Academy of Postgraduate Medicine and in 2007 he also obtained a certificate in gastroenterological surgery at the Slovak Medical University. Since 1997, he has been working at the surgery of the Central Military Hospital in Ružomberok, currently as the head of the central operating rooms.

Since 2012, member of the National Council of the Slovak Republic and member of the Health Care Committee. Head of the Urological Clinic of the SZU FNsP FD Roosevelt Banská Bystrica, the main expert of the Ministry of Health of the SR for urology. For many years he worked in the management of FNsP FD Roosevelt Banská Bystrica (deputy for LPS, director). The main center of interest is innovation, robotic surgery (head of the Center for Robotic Surgery in Banská Bystrica) and transplant medicine (head of the Transplantation Center at FNsP FDR Banská Bystrica).