Evidence-based management of phonological impairment in children is a dynamic process. Speech and language therapists need to evaluate published evidence and use their professional judgement to decide on an intervention plan, evaluate the efficacy of their intervention and re-evaluate decisions. Two case studies are presented to illustrate this process of evidence-based management of phonological impairment in children. Both of the children have a phonological impairment of unknown origin with similar case histories; however, their intervention outcomes were completely different. The two case studies highlight the importance of considering individual differences in the management of phonological impairment in children. They also highlight the importance of integrating up-to-date knowledge with clinical expertise.