This paper presents a portable wireless sensor system for biomedical and environmental applications. The proposed system combines analog front end sensors, processing, memory, and wireless communications integrated on a single chip, allowing for portable, wearable, or implantable use. The circuits presented in this work include a pH to frequency sensor, an impedance to frequency sensor, a Bluetooth receiver front-end, and an 8-bit MIPS processor. All circuits are fabricated on the same chip using a standard 180 nm CMOS technology. Total chip area is 0.332 mm^2 and total power is 4.75 mW.