Many juvenile offenders have reading difficulties, but provision of successful reading interventions in youth facilities is lacking. The reading difficulties are often related to the poor schooling backgrounds of the juvenile offender, who consequently has not developed good reading skills. The computerized flash-card method is based on the theory of sight word reading (Ehri, 2005), which means that the reader has access to a form of sight vocabulary in their memory, and reading becomes more effective when words are decoded automatically. The present study aimed to investigate whether a computerized flash-card method could improve the decoding skills of incarcerated youth. Ten participants were recruited from special residential homes for youths in Sweden. They performed decoding tests before and after the reading intervention, and they received individualized decoding tasks. The intervention was implemented for 15 minutes three times a week over eight weeks. The results showed that after the intervention phonological and orthographical decoding skills had significantly improved. Possible explanations for the positive outcome are discussed in relation to feedback, control, and direct instruction. Based on these promising results, it is desirable to further investigate the computerized flash-card method with larger samples and case-control designs.