Lewis rats received syngeneic heterotopic grafts of jejunum immediately, or after preservation for 24 or 48 hours in Eurocollins solution. Most recipients of tissue stored for 0 or 24 hours remained healthy. Longer storage caused death of the recipients. We evaluated the effect of tissue preservation by comparing grafts stored for 0 and 24 hours with control jejunum at successive intervals up to ten days after transplantation. The physiology and pharmacology of smooth muscle and nerve endings were studied in vitro. Circular and longitudinal muscle in all specimens contracted in response to cholinergic agonists, phenylephrine, and substance P, and was relaxed by isoproterenol and noradrenaline. 5-hydroxytryptamine caused contraction of longitudinal muscle in all cases, and of both muscle layers in grafts that had been stored prior to transplantation. In all grafts, the excitatory innervation was similar to control, while the extrinsic adrenergic inhibition was absent. Prior storage caused an additional loss of intrinsic nonadrenergic inhibition, but this recovered within eight days. These findings indicate that Eurocollins solution might be a useful vehicle for the preservation of donor intestine prior to transplantation, as long as the period of storage does not exceed 24 hours.