It is well known that constitutive models of geomaterials play a very important role in the Computational Geotechnics. After Cam-clay model was extablished, many constitutive models have been developed. Since the behavior of geomaterials is rate dependent, it is preferable to use rate dependent models such as viscoplastic model to the bahvior of geomateials. The time-dependent behavior of soil, manifested as creep, relaxation, and rate sensitivity, comprises indispensable factors for predicting the long-term settlement behavior of soft clay deposits, slope stability, and landslides. In the present report, rate-dependent models, such as viscoelatic and viscoplasticity models are overviewed.