In this paper we empirically investigate the effect of interbank relationship lending on banks’ access to liquidity. Our analysis is based on German interbank payment data which we use to create a panel of unsecured overnight loans between 1079 bank pairs. The data shows that banks rely on repeated interactions with the same counterparties to trade liquidity. For the price of credit, we find that in the run-up to the recent financial crisis of 2007/08 relationship lenders charged already higher interest rates to their borrowers after controlling for other bank specific factors. By contrast, during the crisis borrowers paid on average lower rates to their relationship lenders compared to market lenders. We argue that the observed interest rate differences are in line with relationship lenders having private information about the creditworthiness of their borrowers.