The societal perspective in economic evaluations dictates that costs and effects of informal care are included in the analyses. However, this incorporation depends on practically applicable, reliable and valid methods to register the impact of informal care. This paper presents the conceptualisation and a first test of the CarerQol instrument, aimed at measuring care-related quality of life in informal caregivers. The instrument combines the information density of a burden instrument (encompassing seven important burden dimensions) with a valuation component (a VAS scale for happiness). The instrument was tested in a Dutch sample of heterogeneous caregivers (n = 175) approached through regional caregiver support centres. This first test describes the feasibility as well as convergent and clinical validity of the CarerQol instrument. The seven burden dimensions related well with differences in VAS scores. In all instances, the average CarerQol-VAS scores decreased as the severity of problems increased. Multivariate analyses showed that the seven burden dimensions explained 37–43% of the variation in CarerQol-VAS scores, depending on the model used. The CarerQol seems a promising new instrument to register the impact of informal caregivers in economic evaluations.