Background: Parents and professionals can both play a role in improving children's expressive language development and a number of alternative models of delivery exist that involve different levels of input by these two groups. However, these alternative treatments have not been subject to rigorous comparative analysis in terms of both cost and clinical effectiveness. Aims: To compare, from the viewpoint of the healthcare provider, parent-based intervention (PBI) for preschool children presenting with expressive language delay with current practice observed in an actual healthcare setting where parents of the child follow a professional's advice on a review basis. Methods & Procedures: Two groups of children were compared on a variety of expressive and receptive language assessment measures. One group (n=10) received standard individual general care. The comparison group (n=12) received PBI. Outcomes & Results: After the 6-month study, the results indicated that children who received PBI made significantly greater language gains that children who received current practice. In addition, a cost-effective analysis was conducted. This showed that although the language gains delivered by PBI did incur some additional costs for the healthcare provider, there was no significant increase in cost per outcome gain over general care. Conclusions: Options in the implementation of PBI are discussed that could potentially save costs for the healthcare providers and increase the value of a PBI-based approach.