Organs on a chip are microfluidic models, in which cells are cultured in micrometer-sized chambers perfused by fluidic flow. The concept of creating a body-on-a-chip was born around 2000 for alternative testing to animal models, and to closely replicate the physiological and pathological condition on human cells. Cells cultured in the presence of flow develop features as such morphology, expression of proteins, and perform better than static cultures. Therefore, this model can be helpful in reproducing disease models in dynamic systems and performing ADMET experiments. The aim of this special issue is to collect protocols on designing microfluidic systems, perform computational simulation on organs-on-a-chip, and to collect biological protocols for cell dynamic cultures, pharmacology and toxicology studies, personalized medicine, and disease modelling.