Augmentative biological control is based on the repeated introduction of mass-produced biological control agents as predators or parasitoids with the aim of temporarily controlling or even eradicating pest populations. The different augmentative strategies form a continuum ranging from preventive releases of small numbers of natural enemies prior to the arrival of the pests for a delayed impact (inoculation) to intense, short-term mass releases for a quick and drastic impact on the pest population (inundation). These strategies may also be combined with practices that aim to favour the individual fitness and/or the population establishment of the biological control agents. After briefly reviewing the history of such practices, this chapter explores different challenges currently faced by augmentative biological control linked to the production of biocontrol agents, the underlying business models and the potential existence of non-target effects. Finally, different ways to improve augmentative biological control are investigated, from better selection of biocontrol agent strains to innovations in rearing conditions or supplementation of resources to support the introduced natural enemies. The need to better understand the population dynamics at play or the possible combination of augmentative biological control with entomovectoring techniques are also discussed.