We conduct face-to-face interviews with bank CEOs to classify 397 banks across 21 countries as either relationship or transaction lenders. We then use the geographic coordinates of these banks’ branches and of 14,100 businesses to analyze how the lending techniques of banks in the vicinity of firms are associated with credit constraints at two contrasting points of the credit cycle. We find that while relationship lending does not affect credit constraints during a credit boom, it alleviates such constraints during a downturn. This positive role of relationship lending is stronger for small and opaque firms and in regions with a more severe economic downturn. Moreover, relationship lending mitigates the impact of a downturn on firm growth and does not constitute evergreening of loans.