She died of an infection following a bone marrow transplant to treat Myelodysplastic syndrome, which she had suffered from since the age of 17.

Olszewska-Mróz 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 won two gold medals with the Polish national team at the European Championships: Turkey 2003 and Croatia 2005.

On 22 November 2005, received a state award granted by the Polish President - Gold Cross of Merit for her contribution to the development of sport.

On 11 May 2012, was the premiere of a film Nad życie about Agata Mroz-Olszewska, her private life, illness, marriage and the birth of her daughter.