On the rationale of Bank lending in pre crisis Thailand Evidence from credit files is provided to examine bank lending determinants of Thai commercial banks. Their lending practice follows reasonable patterns as a standard set of variables including indirect risk variables explains much of the variance in interest rate spread. Reflecting institutional differences with mature markets we find higher importance of relationship banking and risk control via credit availability. Information about later default reveals prudent relationship lending. However banks could have made better use of available information about borrowers riskiness. These findings do not support a general verdict of bad banking but indicate room to improve lending decisions.