The Ancón II detention facility was designated as the “model” for redirecting penitentiary treatment based on modern techniques: for this reason, it received inmates imprisoned due to illegal drug trafficking with Rehabilitation Difficulties from the Callao detention facility. Reluctance to participate in psychological actions, a lack of interest in work or educational activities and inadequate personal grooming were observed in the criminological diagnosis. The objective of the applied research was to provide penitentiary treatment. It used the positive reinforcement and modeling techniques as its methodology. The population was 67 inmates, who voluntarily decided to participate in the project. The results showed that 91% of inmates achieved a significant behavioral change while and after participating in the Comprehensive Treatment for Imprisoned Foreigners Program (P.I.T.E.R.) project. It was concluded that applying behavioral techniques facilitates the participation of foreign inmates imprisoned due to illegal drug trafficking with rehabilitation difficulties in penitentiary treatment.