We analyze whether abolishing a copayment of 14 euros for visits to primary care general practitioners (GP) in Helsinki, the capital of Finland, increased the number of GP visits for adults, especially among low-income individuals. Using a difference-in-differences (DD) design and combining several administrative registers from 2011 to 2014, we find that the abolition is associated with only a small increase in GP visits (+0.04 visits annually, or +4.4%, for the whole sample). The increase is driven by low-income adults (+0.06 visits, or +4.5%, at the bottom 40%). Given only one treated cluster and a finite number of comparison clusters, statistical significance of the estimates is inconclusive. Although the point estimates are rather robustly positive, the significance conclusions are sensitive to how we account for clustering.