Non-communicating accessory uterine horns with an endometrial cavity are the most common and clinically significant unicornuate subtype of Müllerian duct abnormality. They are generally associated with symptoms of dysmenorrhea, dyspareunia, infertility, endometriosis, adhesions, and life-threatening cornual pregnancy. Treatment options include surgical resection of the rudimentary horn, hysteroscopic recanalization, and endometrial ablation. Currently, laparoscopic resection is the recommended treatment choice. Dissection of the rudimentary horn from the unicornuate uterus is the most challenging part of this procedure and may compromise the remaining unicornuate uterus wall. Here we describe a case of laparoscopic coring-type resection of a non-communicating functional rudimentary horn firmly attached to the unicornuate uterus, by using hysteroscopic assistance. The use of hysteroscopy, adjunct to laparoscopy, facilitates the coring-type resection and may strengthen the remaining myometrial scar.