Jef Mulder is ENT surgeon at the Radboud University Nijmegen Medical Centre. In his first years as a full-time staff-member in Nijmegen, he mainly did Rhinology and Functional Endoscopic Sinus Surgery. Later on he specialized in Otology and Neurotology.

Now his clinical practice is almost entirely devoted to otology, cochlear implantation and implantation of middle ear devices. Moreover, for more than 15 years he has experience in –mainly translabyrinthine and infratemporal- skull base procedures.