We wanted to present the usage of membrane bioreactors for municipal wastewater treatment plants. In industries such systems are widely spread contributing to improve wastewater treatment. With increasing standards on discharges from wastewater treatment plants began usage of membrane bioreactors at municipal treatment plants. The aim of the thesis was to describe the process of wastewater treatment with membrane bioreactors and to present advantages and disadvantages of these systems. Companies that produce membrane bioreactors have different ways of approaching to development. So there has been the emergence of several types of membrane systems, materials and procedures in the proper functioning of membrane bioreactors. We have presented the most commonly used systems, which are already well proven for usage for municipal wastewater treatment plants, since they have been in operation for several years. By studying the literature it showed that the usage of membrane bioreactors for municipal wastewater treatment plants still has some drawbacks. Particularly the operating costs are higher than by conventional biological wastewater treatment plants, which is result of membrane exchange. Since the membrane bioreactors are not commonly used at this type of treatment plants the costs of installing the system are therefore also higher. Some of setbacks of membrane bioreactors can be found in intense maintance and cleaning of the membranes.