This paper presents a method to integrate biocompatible passive microfluidic systems within a sensing platform to allow continuous analysis of sweat in a wearable microsystem. The technology is promising for miniaturization of systems to enable access to biochemical information at the surface of human skin. The microfluidics are originally designed to work with ultra-low volumes of liquid to enable sweat analysis at any physiological situation (during intense physical activity or when at rest). Flow rates vary from 10s to 100s of pico-liters per second which can be adjusted by design. Capillary forces are used to move the liquid inside the microchannels in order to avoid power consumption. The SU8-based process is compatible with standard semiconductor techniques making it scalable, and suitable for integration with different sensing technologies. In this work, the microfluidic devices have been designed and integrated on top of ISFET devices.