The effectiveness of cancer treatment and reducing cancer-related deaths strongly depends on the early diagnosis of cancer cells or related markers. Different nanomaterials have been applied for diagnosis, treatment and management of cancers. Between these, carbon dots (CDs) have unique properties. These include: low cost for synthesis/fabrication, high brightness, cell permeability and photostability, good intracellular solubility, high affinity and specificity to targets, high surface area and nontoxicity. They are used not only as an ideal fluorescent probe or electrochemical platform for biosensing but also they can be applied as a novel label for bioimaging. In this review, we considered recently developed electrochemical and spectroscopic biodevices for cancer markers and cancer cells analysis. Furthermore, the application of CDs as specific emerging fluorescent probe in bio-imaging of cells was also highlighted. This review opens new windows for synergistic efforts of researches in chemistry, biology and medicine for management and diagnostic of cancers.