Mandibular molars can have an additional root located distolingually (the radix entomolaris) or mesiobuccally (the radix paramolaris). If present, an awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment. This paper describes two case reports on the presence of radix entomolaris in mandibular first molar which focus on its clinical approach for identification, detection and endodontic management.