Many researchers have studied aggregation of microgel particles; however, the majority of these studies have been limited to singlecomponent system in which homoaggregation is observed. On the other hand, less attention has been given to multi-component systems whereby heteroaggregation is seen. As such, heteroaggregation is not only important in various applications but is interesting from a fundamental point of view. In such a way, aggregation is driven not only by attractive electrostatic interactions, but also the presence of repulsive forces. Therefore this review discussed on the theoretical background, external effects on heteroaggregation and their potential applications.