The understanding and adherence to postoperative care instructions may be influenced by how they are presented by the professional interfering the recuperation process after surgery. The aim of this study was to evaluate the effect of a postoperative phone call follow-up compared with a traditional verbally and written instructions regarding compliance of postoperative recommendations after third molar surgery; and secondly, to discover the main points of non-compliance. A randomized clinical study was performed including patients that underwent surgical extraction of an impacted mandibular or maxillary third molar in the Oral Surgery Unit of the University of Valencia from January 2016 to January 2017. Patients were randomly assigned to one of three different test groups according to how the post-operative instructions were delivered: brief written instructions, written extended instructions or brief written instructions plus a phone call follow-up at 3-day postoperative period. Patients were interviewed about their adherence to the instructions one week after surgery. The significance level was set at p<0.05. The higher score of compliance was found to the phone call follow-up group (p=0.001). No statistically significant differences were found between brief written group and the group that received written extended instructions. In the phone call follow-up group all variables assessed to the compliance were fulfilled. To brief written and written extended instructions groups, the main points of non-compliance were hygiene and smoking (p<0.001, p=0.026, respectively), and tended towards significance for chlorhexidine rinses and antibiotic, analgesic and anti-inflammatories medication prescribed. Telephone call follow-up can promote patient adherence to postoperative recommendations after third molar surgery. The main factors of non-compliance were not maintain a proper hygiene and not smoking, followed by not performing chlorhexidine rinses and not following medication prescribed.