Vermeulen was the leader of the Amsterdam Jazz Quintet with which he recorded four CD’s. In addition, his trio has accompanied artists such as Sal Nistico, Tom Harrell, Chet Baker and Jesse van Ruller. He has been digging deep into the music of Thelonious Monk with the band Ugly Beauty, a group with drummer Han Bennink and saxophonist Benjamin Herman. In recent years he has become interested in free forms of improvisation. With saxophonist Frans Vermeerssen he started the improbop group Talking Cows. They have undertaken several international tours together and play regularly in clubs and festivals. Their 3rd cd 'Almost Human' got excellent reviews in the international jazz press culminating in a 4,5 star rating in DownBeat Magazine. Robert is a piano teacher at the ArtEZ Conservatory in Arnhem.