Career
A professional competitor since 2009, Omielańczuk has also formerly competed for KSW.
Early career
Omielańczuk made his professional debut in 2009, competing primarily in regional promotions across the Eastern Europe, including KSW, where he compiled a record of 15 - 3 before signing with the UFC in the spring of 2013. Ultimate Fighting Championship
Omielańczuk made his promotional debut against fellow newcomer Nandor Guelmino on September 21, 2013 at UFC 165. Omielańczuk faced Jared Rosholt on April 19, 2014 at UFC Fight Night 39.
Rosholt defeated Omielańczuk via unanimous decision.
Omielańczuk was expected to face Soa Palelei on November 8, 2014 at UFC Fight Night 55. However, Omielańczuk was forced to pull out of bout with a broken thumb and was replaced by Walt Harris.
Omielańczuk faced Anthony Hamilton on April 11, 2015 at UFC Fight Night 64. Omielańczuk lost the fight by unanimous decision.
Omielańczuk was expected to face Konstantin Erokhin on July 18, 2015 at UFC Fight Night 72.
However, Erokhin pulled out of the fight in late June citing an injury and was replaced by promotional newcomer Chris de la Rocha. Omielańczuk faced Jarjis Danho on February 27, 2016 at UFC Fight Night 84.