Report on a programme of archaeological monitoring and recording, conducted during groundworks for the construction of new extensions to the rear of 7 St Leonard's Street, Stamford. Evidence for medieval iron working in this part of Stamford was revealed in the form of a dump of smelting and smithing slag. The deposit included sherds of 12th century Stamford ware pottery and fragments of animal bone. The iron-working waste was sealed by post-medieval levelling layers, deposited prior to the construction of the present house on the site, in the 17th century. Several redeposited fragments of medieval Bourne ware type pottery and tile were also recovered from the overlying subsoils.