Abstract: To develop an efficient and simple method for detecting Single Nucleotide Polymorphisms (SNPs) is important because nucleobase mutations may cause genetic abnormalities. Excimer formation by modified pyrene has been utilized by many research groups for designing unique classes of DNA probes but the intensity of excimer fluorescence may be influenced by terminal overhangs in the complementary sequences. The aim of the study was to justify the effect of chain length of the complementary strands on the excimer fluorescence intensity. In the present study, a simple method has been developed for SNP detection using a novel 12-mer DNA probe bearing two consecutive silylated pyrene units that could efficiently detect perfectly matched and single base mismatched complementary sequences. The oligoDNA probe has been synthesized by automated DNA synthesizer using phosphoramidite chemistry. The probe gives marked excimer fluorescent signal only upon binding to the fully matched complementary DNA strand. However, the excimer signal was significantly decreased in the single stranded form as well as in the duplexes with single base mismatched complements. And virtually there was no effect of the length of the complementary DNA strands on the intensity of excimer fluorescence.