In a longitudinal intervention study, the effects of phonological training with articulation for children in a preschool class were analyzed. In total, 69 students participated, divided into an experimental group of 39 and a comparison group of 30 students. The intervention consisted of phonological training with articulation and lasted throughout the preschool class year; in total, 2700 minutes were spent on this training for the experimental group. All participants were tested individually on pre-reading skills on four test occasions: before the intervention started, mid-term, immediately after the end of the intervention and, finally, a follow-up 6 months after the intervention was completed. Based on their pre-reading skills, the participants were divided into two different subgroups, those at risk of developing reading difficulties and those not at risk. The results showed greater progress at the follow-up test of both the at-risk and not-at-risk subgroups of the experiment group in word decoding and phonological ability than the comparison group. The positive results applied both to speech-sounds and words included in the training program as well as new speech sounds and words not included in the program, thus providing evidence for transfer effects.