Observation of parental sensitivity in a standard procedure, in which caregivers are faced with the same level of infant demand, enables the comparison of sensitivity "between" caregivers. We developed an ecologically valid standardized setting using an infant simulator with interactive features, the Leiden Infant Simulator Sensitivity Assessment (LISSA). The infant simulator resembles a real infant in appearance and crying sounds. In a previous study, we documented the LISSA's reliability and validity in a sample of 181 female undergraduate students (Voorthuis et al., 2013). In the current study, we tested the convergent validity in a sample of 34 mothers who were observed during free play with their own child as well as with the LISSA. Sensitive parenting behaviour was rated independently with the Ainsworth Sensitivity Scale (Ainsworth et al., 1974). Sensitivity with the LISSA was strongly correlated to sensitivity to the mother's own child, r?=?0.53, p?=?0.001. Mother-reported infant temperament was not associated with sensitivity to the mother's own child, and the mother's own infant's temperament did not moderate the correlation between sensitivity with the LISSA and sensitivity to the mother's own child. We discuss the potential of the infant simulator for research on sensitive parenting in parents and non-parents, for (prenatal) preventive interventions, and for clinical practices.