The capacity of the 3D-organoid cultures to resemble a near-physiological tissue organization and to mimic - to a certain degree - organ functionality, make organoids an excellent model for applications spanning from basic developmental/stem cell research to personalized medicine. Here, we review key findings achieved through organoid technology, and we discuss applications such as disease - and tumour modelling, correction of genetic mutations and understanding gene - and cell functions. Finally, we discuss future developments in the field.