Ralphi Rosario has been played over 40 times on NTS, first on 1 July 2013. Ralphi Rosario's music has been featured on 45 episodes.

Ralphi Rosario, aka Ralphie Rosario is a leading deejay in the house music scene. He virtually coined the phrase House Music along with the crew of Chi-Town radio show Hot Mix Five. Through this channel, he was able to blast Chicago's airwaves with the new and exciting sounds of house music for most of the 1980s. In 1987 Rosario released the house music anthem, "You Used To Hold Me," with the vocals of Xavier Gold. The track marked a pivotal point in house music history and helped the genre break into Europe and later in the United States.

Rosario has worked his remixing magic on artists, including INXS, the Shamen, Jomanda, Culture Beat, Gloria Estefan, Dee-Lite, Pet Shop Boys, Madonna, Michael Bublé, Mariah Carey, Ricky Martin, Kelly Clarkson and Pussycat Dolls. Recently he has returned to his underground house roots with several releases on the Afterhours imprint. "Gotta New Love" is remixed by Classic Music co-owner Derrick Carter and is blessed with Donna Blakely's diva tones. The "4 am Bonus Mix" of "Timbalin" is a tough primetime track with some sublime freeform keys.