Although today endoscopy has established its place in medical diagnostics, it has not yet exceeded the function of a qualitative, subjective observation method. Combination of coherent metrology, especially holographic interferometry, with endoscopy opens the possibility for high-resolving, non-contactive, non-destruc- tive intra-cavity measurements. In addition, modern developments in micro-optics provide essential miniaturization of endoscopic devices. The introduction of micro-optics into holographic endoscopy raises problems due to limitations in op- tical signal-to-noise ratio (SNR) caused by small apertures of the image transmit- ting systems as well as due to restrictions of common holographic recording mater- ials for in-situ recording and reconstruction with fast-repetition rate and high (line) resolution. Three developments in micro-optics can help to overcome these obstacles and give main impulses to actual progress in holographic endoscopy: - micro-optical gradient-index imaging systems, - micro-optical (single-mode) imaging fiber bundles, and - electro-optical crystals as holographic storage devices.