Over the last decade, array detection has been developed to qualitatively assess the presence of genetically modified organisms (GMOs). To date, DNA array systems have the highest capabilities as a result of GMOs analysis. We describe the construction of an array platform in the sandwich hybridization format for the detection of transgenic promoter of Cauliflower mosaic virus (CaMV; p35S). Sequence-specific signal development has been achieved by a sandwich complex composed of a surface immobilized capture probe and a fluorescein-tagged signal probe, which are partially complementary to the p35S oligonucleotide. We used poly-l-lysine-coated glass slides as support material, on which capture probes were immobilized by a heterobifunctional cross-linker. The comparative results of optimization studies including cross-linker types probe concentrations and hybridization conditions (sequence, temperature and duration) were reported. An optimum hybridization signal was obtained with a 32.5 C-0 cross-linker, 10 mu M capture and 20 mu M signal probe concentrations, respectively. A relatively short hybridization time (2.5 h) provided reproducible array signals. No significant effect of hybridization sequence on the fluorescence intensity was observed. The described platform can specifically detect label-free transgenic sequences with a target of 0.01 mu M concentration, while the optimized system exhibits great potential for the application of different GMO target sequences (p35S, tNOS, bar and cry) to multiplex array formats.