The content of meconium in amniotic fluid(AF) is important for assessing the risk of several perinatal problems such as asphyxia, meconium aspiration syndrome and various perinatal infections. This estimate is usually performed subjectively by visual inspection. The purpose of this study is to develop the objective method for quantitative measurement of meconium content in AF. Absorption spectra and meconium-crit of the solutions with various concentrations of meconium were measured. EfFects of filtration and blood contamination on the measurement of meconium content were also estimated by the same methods. Optical densities(OD) were correlated with concentrations of meconium in the whole range of scanned wavelengths. A specific peak of meconium was not available but the highest OD around 410 nm was shown. OD were linearly related to the concentrations of meconium. Meconium-crits were also well-correlated with the concentrations of meconium. Filtration of AF as well as blood contamination in AF severely affected the measurement of meconium content in AF. From the results of this study, both the spectrophotometric method and meconium-crit couid be objective methods for measuring meconium content. Both methods had merits and shortcomings. Filtration and blood contamination should be avoided for the measurement of meconium content in AF. We hope that both or either one of the two methods will be clinically used.