Micro-device design, modelling and simulation are important aspects of our work at SINTEF-MiNaLab. Due to the rapid progress in the manufacturing of miniaturized smart microsystems, the numerical simulation tasks are essential steps in making predictions before experiments are done, as well as interpreting the data after experiments. During the last ten years there have been significant developments in the modelling community around a multiphysics analysis approach, which constitutes a cost-effective and time- saving alternative to the traditional "trial and error" experimental approach. By coupling the physics between different disciplines, the simulation assists also the designer in making decisions with a view to find optimized structures and solutions under technological and economical restrictions. In this talk, we discuss and review various aspects of our microsystems multiphysics simulations done at MiNaLab. Various applications, capabilities and challenges are exposed.