We demonstrate a ?eld-portable upright and inverted microscope that can image specimens in both re?ection and transmission modes. Thiscompact and cost-effective dual-mode microscope weighs only 135 grams (<4.8 ounces) and utilizes a simple light emitting diode (LED) to illuminate the sample of interest using a beam-splitter cube that is positioned above the object plane. This LED illumination is then partially re?ected from the sample to be collected by two lenses, creating a re?ection image of the specimen onto an opto-electronic sensor-array that is positioned above the beam-splitter cube. In addition to this, the illumination beam is also partially transmitted through the same specimen, which then casts lensfree in-line holograms of the same objects onto a second opto-electronic sensor-array that is positioned underneath the beam-splitter cube. By rapid digitalreconstruction of the acquired lensfree holograms, transmission images (both phase and amplitude) of the same specimen are also created. We tested the performance of this ?eld-portable microscope by imaging various microparticles, blood smears as well as a histopathology slidecorresponding to skin tissue. Being compact, light-weight and cost-effective, this combined re?ection and transmission microscope might especially be useful for telemedicine applications in resource limited settings.