A simple fiber temperature sensor based on Michelson interferometer is investigated experimentally. The sensor is formed successive splicing of a single mode fiber (SMF) spliced to a short section of multimode fiber (MMF) followed by another SMF, which also known as single mode-multimode-single mode (SMS) structure. Temperature response of three different sensor lengths of 10 mm, 20 mm and 30 mm are experimented with increasing and decreasing temperature. The sensor exhibits good linearity, stability and repeatability for the test range from room temperature to 180 °C. The highest sensitivity is attained by the 10 mm sensor with response ~0.108 nm/°C. Factors that affect sensitivity are discussed and related issues are addressed. This sensor is most suitable for low to intermediate temperature applications.