During the lifetime, plants interact with numerous pests with diverse modes of attack and lifestyle. The primary immune response evolved toward the recognition of the organisms that interact with the plant and the translation of this recognition into a defense response specifically directed against the invading organism. In addition to this induction, plant defenses may also be primed. This kind of resistance often acts systemically throughout the plant and is effective against a broad spectrum of pests. There are different types of induced resistance, depending on the organism or inducer that interacts with the plant. The plant-signaling molecules salicylic (SA) and jasmonic acids (JA) play an important role in the induced disease resistance pathways with a possible antagonistic interaction between the SA-dependent systemic acquired resistance (SAR) pathway, which is induced upon pathogen infection, and the JA-dependent induced systemic resistance (ISR) pathway. In general, defense responses are vital but costly for plants. Thus, instead of maintaining them continuously, they can be primed and subjected to tight regulation, rapid activation, and spatial and temporal concentration, important factors for the success. However, the cost for this process should be analyzed in specific experimental designs that include the pathogen challenge. The aim of this paper is a simple approach to some concepts about the induced resistance, different induction alternatives, as well as possible inductors, signalling pathways and the resistance induced costs for the plant.