Using 11years of monthly Italian bank-by-bank data, this paper correlates the bilateral amounts and the identity of each interbank borrower and lender with a long list of explanatory variables. The results show that interbank customer relationships, i.e. stable and strong relationships between pairs of borrowing and lending banks, do exist in Italy, that they persist over time, and that they functioned well during the crisis, enabling the healthier banks to provide and the troubled ones to receive funds.