The present study was intended to examine a basic scheme to determine the biochemical oxygen demand(BOD) of livestock wastewater by means of six individual dissolved oxygen(DO) sensors and its multi-measurable meter. Maximal point of the first order time derivative of the DO difference between DO distribution of sterilized livestock wastewater and that of non-sterilized livestock wastewater, was considered as the oxygen uptake rate(OUR) of microorganisms in livestock wastewater, as determined to be 0.00074 mg $O_2/{ell}{cdot}sec$. The present study showed that there was a fair linear relationship(97.72%) between maximal OUR and BOD values of livestock wastewater, the latter being determined by classical Winkler azide method. It was thus concluded that the present multi-biosensor system might be applicable to an on-line system for measurement of BOD of livestock wastewater.