Abstract* Backgrounds The retention of the maxillary complete denture may be influenced by adequate recording in the patient’s mouth, marking, and carving of the post-dam on the maxillary cast. Failure to do so may lead to loss of retention. Successful denture construction with patient’s comfort could be achieved by effective methods of recording, marking, and carving of the post-dam. The aim of the study was to assess Iraqi dentists in their knowledge and application of the post-dam in maxillary complete dentures. Methods Questionnaires were distributed randomly through online Google Forms and 118 Iraqi dentists with different academic degree participated in the study. A multinomial logistic regression model was also used to assess the nominal outcome variables. Results A High percentage of 90.7% of Iraqi dentists with different academic degree stated that they had the knowledge about the vibrating lines and their location and 84.7% stated that they mark the post-dam on the master cast, while 15.3% stated that the dental technician marks it. More the half (52.5%) of the participants carved the post-dam, while 47.5% of the participants stated that the dental technician did it. For participants not marking the post-dam, 30.5% of the participants stated they depend on the dental technician in marking and/or carve the post-dam, while the fear of denture failure and loss of retention was observed in 25.4% of the participants, followed by 24.6% of participants forgetting to carve, 10.2% of participants had no information about carving, and 9.3% participants found it was difficult to carve. Conclusions Within the limitations of the study, most Iraqi dentists with different academic degree stated that they had the knowledge on the location of vibrating lines. However, recording and carving the post-dam was influenced by the dentist’s personal preference and their dependency on the dental technician.