Agroinfiltration is a very fast and powerful method to express in planta any sequences in a transient fashion. Agroinfiltration has proven very useful for the overexpression of proteins in the infiltrated zone when a short-term effect can be informative. However, it has been a real success story in the induction of local and eventually systemic silencing. Here, we describe the use of agroinfiltration for the induction of local silencing of an endogene or a transgene, for the systemic silencing of a transgene and for co-infiltration assays. We also provide protocols for the evaluation of the efficiency of the assay, by detecting the specific siRNAs characteristic of RNA silencing and measuring the effects on the target sequences.