© 2017 IEEE. We developed a wearable flexible chemical pH sensor consisted of ion sensitive field effect transistor (ISFET) integrated with a printed flexible physical temperature sensor by developing material systems and optimizing the fabrication process as the first proof-of-concept. A major role of flexible ISFET is to measure pH value of sweat by putting it on a skin. The integrated temperature sensor is used to monitor skin temperature as health condition and to compensate pH value measured by ISFET because the characteristics of ISFET is changed by temperature. By analyzing temperature sensor and ISFET including temperature effect, we could successfully measure real-time pH value and skin temperature. The results show that this flexible integrated device has a high potential to be wearable chemical sensing from sweat in addition to physical health conditions.