Orthotropic small intestinal transplantation (SIT) was performed in outbred 20 pigs. The interdigestive motor patterns were evaluated using strain gage (SG) force transducers. Seven pigs without SIT were treated as control (C) group. Based on the obtained data, the group, which could be detected the migrating motor complex (MMC) in the graft and alive with adequate oral feeding, was regarded as functional graft (FG) group, whereas the group which had available data recorded within 10 days before the death due to rejection was regarded as rejection (R) group. The MMC was analyzed using following parameters: duration; amplitude; and interval. In group FG, all parameters were almost same as group C, thus suggesting that the allograft in group FG had a normal motor function. In contrast, all parameters in group R were significantly lower than those in group FG, suggesting that the motility in group R was impaired. The SG method could monitor the real-time motility and was efficient for detecting the rejection of SIT.