A modified RNA in situ hybridisation method was tested on oil palm fruits and inflorescences. This method was efficient in preserving the morphology of tissues and preventing tissue damage due to dryness and shrinkage. The tissues were dehydrated with absolute 1-butanol followed by vacuuming with molten paraffin at 60^οC. The in situ hybridisation analyses were carried out with sense and antisense probes of ELF1-α to examine and compare the condition of these tissues treated with the modified and the standard methods. The modified method showed that the permeability of tissues increased with absolute 1-butanol treatment and application of vacuum at 60^οC facilitated penetration of the molten paraffin into the centre of the tissues. This resulted in well preserved tissues that remained intact during sectioning.