The effect of time-gating method in Raman spectroscopy for fluorescence suppression of Iranian region calcite is investigated. Experiments are done using an Nd:YAG laser with a pulse durations of 10 ns at wavelength 532 nm. Seven samples from different places are examined. In order to obtain the optimum gate width for fluorescence suppression, a series of experiments is carried out at different gate widths. Raman-to-fluorescence (R/F) and fluorescence-to-laser peak (F/L) ratios are compared at gated and nongated experiments. Applying the optimum gate width leads to an effective reduction of fluorescence background and improvement in both ratios of R/F and F/L. Raman signals of some samples in nongated experiments are completely hidden by fluorescence while emerged in gated experiments.