Raising a child with autism spectrum disorders presents families with exceptional caregiving challenges. Consequently, parents, particularly mothers, evidence unusually high stress levels. Previous research has identified relevant variables that help explain maternal stress: the child's behavior problems, social support and the sense of coherence (SOC) as a perception of problem. However, there are few longitudinal studies demonstrating how these variables correlate over time. We present a longitudinal study of 21 Spanish mothers of children with autism spectrum disorders (ASD) at two measurement time points over an interval of 4.5 years. Our aims are to examine the predictive relationships of these variables (behavior problems, social support and SOC) to stress and to analyse their changes over time. Data were collected through questionnaires. The results of the regression analysis (multiple adjusted R 2= .45, ƒ2 = .82) highlight the predictive values of SOC (adjusted R 2 = .31) and the initial stress levels (Δ adjusted R 2 = .14) for stress levels 4.5-years later. Our study used t-tests to compare measurements at the two time points; results demonstrate the permanence of stress levels and behavior problems and the effects of reduced social support and increased SOC levels (t(20) = 2.48, p = .02, Cohen's d = .63; t(20) = -4.22, p < .001, Cohen' d = .58). Implications for interventions are discussed.