This study examined the relationship between maternal mental health problems and both caregiving time and experience of time pressure for 216 mothers of children with autism. Data describing caregiving time was obtained using 24-h time-diaries. Standard questionnaires were used to assess time pressure, social support, children’s emotional and behavioural problems, and maternal mental health problems. After adjusting for the effect of children’s age, maternal social support, and children’s behaviour problems, time pressure but not hours of caregiving, had a significant positive relationship with maternal mental health problems. Findings suggest that the quality of home-based care for children with autism may be adversely affected if time pressure experienced by caregivers compromises their mental health and well being.