The present invention aims at providing a biological information monitoring system capable of detecting biological information from the multiple loci of the right and left sides of the living body to early determine physical abnormalities with higher accuracy than that of the conventional art. To attain the object described above according to the present invention, there is provided a biological information monitoring system comprising a plurality of biological information sensor modules 1A and 1B attached to the right side and left side of a subject body, which sensor modules 1A and 1B each incorporate a biological information sensor for detecting biological information, and a communication means capable of wireless radio communication for the biological information. At least one of the biological information sensor modules 1A and 1B includes a determination means for performing determination of abnormality by comparing the biological information detected by one biological information sensor in one of the sensor modules with biological information sent from the other biological information sensor module through the communication means.