We developed a new method for an objective assessment of the meconium content in amniotic fluid. By establishing a standard scale through a serial dilution of a known amount of meconium into the amniotic fluid, we developed a new method 'mecometer 'that can objectively measure the meconium content in meconium-stained amniotic fluid samples. The objectivity and reliability of this mecometer were verified by 300 student volunteers. At least 70% of the volunteers could objectively measure and digitally describe the meconium content in meconium-stained amniotic fluid samples. We believe our newly developed mecometer is a very simple, reliable, and portable method, not requiring any instruments.