This case report presents an unusual occurrence of bilaterally symmetric maxillary first molars with four roots (two palatal roots) and four canals. This atypical root morphology was confirmed with cone beam computed tomography. Root canal treatment was performed for both first molars and coronal restoration was accomplished with resin composite and a full coverage porcelain crown. The clinician should always be aware of unusual root and canal morphology. The concurrent usage of the dental operating microscope and cone beam computed tomography, in addition to the thorough knowledge of the morphology of these teeth with careful clinical and radiological examination, is essential for successful clinical results. Keywords: cone beam computed tomography, dental operating microscope, maxillary first molar, root canal treatment, unusual root morphology