In this paper, we review LiNbO3-based devices and technologies from both materials and device processing techniques. However, all the relevant areas cannot possibly be covered; we limit the scope of the paper to electrooptic devices. Also, we mostly focus on our own activities at Sumitomo Metal Mining. First, materials-related issues such as the uniformity and consistency of the substrate crystal as assessed by the variability of directional coupler coupling length are summarized. The photorefractive damage resistance is also reviewed; the dependence on the substrate quality and input laser wavelength. Second, taking the case of the multi-function gyro chip, we review and discuss the use of both Ti-indiffused and proton-exchanged waveguides on a single chip.