Microscale manufacturing is growing rapidly, particularly in the biomedical, electronics and aerospace areas. Therefore, the ability of microcutting techniques, such as micromilling needs to be improved in order to produce complex features with good surface finish. It is essential to inspect the state of cutting tool while the operation is being performed to get high surface finish. Like in conventional milling process, it is difficult to utilize the sensors for this purpose in micromilling process. Hence, tool state monitoring in micromilling become difficult. This paper summarizes the approaches for indirect methods for tool state monitoring in micromilling that has been used and documented.