In the last few years, 3D printing has emerged as a promising alternative for the fabrication of microfluidic devices, overcoming some of the limitations associated with conventional soft-lithography. Stereolithography (SLA), extrusion-based technology, and inkjet 3D printing are three of the widely used 3D printing technologies owing to their accessibility and affordability. Microfluidic devices can be 3D printed by employing a manufacturing approach from four fundamental manufacturing approaches classified as (1) direct printing approach, (2) mold-based approach, (3) modular approach, and (4) hybrid approach. To evaluate the feasibility of 3D printing technologies for fabricating microfluidic devices, a review focused on 3D printing fundamental manufacturing approaches has been presented. Using a broad spectrum of additive manufacturing materials, 3D printed microfluidic devices have been implemented in various fields, including biological, chemical, and material synthesis. However, some crucial challenges are associated with the same, including low resolution, low optical transparency, cytotoxicity, high surface roughness, autofluorescence, non-compatibility with conventional sterilization methods, and low gas permeability. The recent research progress in materials related to additive manufacturing has aided in overcoming some of these challenges. Lastly, we outline possible implications of 3D printed microfluidics on the various fields of healthcare such as in vitro disease modeling and organ modeling, novel drug development, personalized treatment for cancer, and cancer drug screening by discussing the current state and future outlook of 3D printed ‘organs-on-chips,’ and 3D printed ‘tumor-on-chips.’ We conclude the review by highlighting future research directions in this field. © 2021, Zhejiang University Press.