Autism spectrum disorders (ASD) are associated with a substantial economic burden, but there is little evidence of the costs in the early years; the period in which children are increasingly likely to be diagnosed. We describe the services used by 152 children aged 24-60 months with autism, report family out-of-pocket expenses and productivity losses, and explore the relationship between family characteristics and costs. Children received a wide range of hospital and community services including relatively high levels of contact with speech and language therapists and paediatricians. Total service costs varied greatly (mean £430 per month; range £53 to £1,116), with some families receiving little statutory support. Higher costs were associated with increasing age and symptom severity.