Detection of low levels of light is one of the key aspects in medical and space applications. Silicon Photo-Multipliers, a novel type of avalanche silicon photo-detector with Geiger mode of operation show promising results and offer superior design options. The performance characteristics of the SiPM are studied and presented in this paper. The leakage current, dark rate and internal gain are characterized as a function of temperature. The investigation has been done in the framework of the DASiPM Collaboration in the contest of the INFN/FBK-irst MEMS project. © 2007 IEEE.