Agata Mróz-Olszewska (born on April 7, 1982 in Dąbrowa Tarnowska – June 4, 2008 in Wrocław) was a Polish volleyball player, and a member of the women national team. She died of an infection following a bone marrow transplant. The transplant was to treat Myelodysplastic syndrome, which she had suffered from since the age of 17.
Olszewska-Mroz began her career in Tarnovia Tarnów, then moved to SMS Sosnowiec, WSBiP Ostrowiec Świętokrzyski and BKS Stal Bielsko-Biała, where she was twice champion of Poland (2003 and 2004). She also played for the Spanish team Grupo 2002 Murcia, winning both the Championship of Spain and the Cup of Spain tournament (2007). In 2007 she gave up her volleyball career because of her bone marrow disease. Polish and international volleyball authorities as well as numerous fans organized a campaign to help her.
For her sport achievements, on November 22, 2005 president Aleksander Kwaśniewski awarded her a Golden Cross of Merit.
She is survived by her husband Jacek Olszewski and daughter Liliana, who was born on April 4, 2008, just two months before Mróz-Olszewska death.