Financial hurdles frequently make people forego or postpone necessary care. Targeted reductions in healthcare prices may help to improve access to essential healthcare for the poor. This paper evaluates to what extent simple behavioural incentives like letters and flyers sent to low-income groups stimulate the participation in a beneficial health insurance plan. Using a large-scale randomized field experiment we study the effect of contacting potential beneficiaries on the take-up of the Increased Reimbursement (IR) for healthcare in Belgium. In line with previous behavioural evidence, we find a substantial effect of around 15 percentage points on the take-up of IR. This effect differs strongly across regions and between population groups.