Biological tissue are generally low in intrinsic contrast to transmitted-light microscopy. The development of contrast-enhancing methods such as phase contrast allowed the investigation of highly transparent specimens by exploiting differences in refractive index and optical path to produce contrast. Phase contrast microscopy has become a ubiquitous workhorse technique throughout cell biology and physiology, yet the optical design has remained relatively unchanged; consisting of a light source, collimating optics, phase annulus, and condenser producing a hollow cone of illumination which passes through the sample. On the detection side, the use of phase contrast objective lenses introduces a complementary ring of phase-retarding and attenuating material to alter the phase relationship of the undeviated illumination with respect to light deviated by passage through the sample. By interfering these two partially coherent rays onto the detector, contrast is obtained by the phase shift in transiting the sample.Methods: Presented is a novel implementation of phase contrast microscopy, in which condenser optics are entirely eliminated, yielding a condenser-free yet highly effective method of obtaining phase contrast. A ring of light emitting diodes is positioned within the optical light-path such that observation of the back focal plane of the objective places this ring, observed at virtual “infinity” with respect to the objective focal length, in appropriate conjunction with the phase ring. A range of ex vivo cell preparations, prepared slides, and cell lines were used to verify the performance of the system. Results: It is demonstrated that true phase contrast is obtained, whose geometry can be arbitrarily manipulated to provide a range of workingdistances and form factors. LED-ring phase contrast is demonstrated at phase position L, 1, 2, 3 and 4 across a range of magnifications. Further demonstrated is phase contrast microscopy at high magnification and numerical aperture (100x, 1.4NA) using external phase rings, and the use of LED-based phase contrast illumination in conjunction with scanning probe microscopy, in particular scanning ion conductance microscopy (SICM). Concurrent phase contrast and SICM imaging is demonstrated for a range of cultured cell lines; including ARPE-19, 3T3 fibroblast, and Caco-2 cells.Conclusion: Condenser-free phase contrast microscopy using LED rings has significant potential to benefit physiology and cell biology by providing for arbitrary working distances inilluminating optics. By eliminating the need for a condenser assembly a range of concurrent imaging and measurement techniques will be technically facilitated through the provision of extra room to work. In addition the compact, low power, and versatile nature of LED illumination will further lend itself to miniaturisation and modification of existing phase contrast microscopy schemas in the future.