Methods to minimize the effect of cold ischaemia on porcine islet isolation were investigated. Forty pancreata were randomized to intraductal collagenase delivery in University of Wisconsin solution (UW) or Hanks balanced salt solution (HBSS) (control) both before and after 65 min of cold pancreas storage. Collagenase was also administered in a specially designed cold storage solution (University of Leicester solution, ULEIC), before cold storage. Median islet yield was significantly greater if the pancreas was distended with collagenase in either UW (21 524 islet equivalents (IEQ) per g) or ULEIC (19 814 IEQ/g) before cold storage, compared with that after distension with HBSS (6924 IEQ/g) following cold storage (P<0·05). Islet fragmentation, islet purification and glucose-stimulated insulin release were not significantly different after collagenase delivery in either UW or ULEIC compared with those after administration in HBSS. It is concluded that porcine islet yields can be improved significantly by intraductal collagenase administration in either UW or ULEIC immediately after excision of the pancreas.