RNase free water or TE buffer (= 10 mM Tris-Cl, pH 8.0 + 1 mM EDTA pH 8.0) work well. Keep the aliquots frozen at -80 C.

My lab doesn't have the equipment to store RNA at -80 C. I had used TE buffer before and store at -20 C but it didn't work. Anyway, thanks for your recommendation.

In that case perhaps storing the rna oligo as an ethanol precipitate in aliqouts at -20 would work better. If the amounts are very small then adding a co precipitant like glycogen would help precipitation.

Paul Rutland Thanks for your suggestion. I'll try this way.