In order to survive at temperatures of ≥60°C, thermophilic prokaryotes (Archaea and Eubacteria) have adopted different strategies. These strategies include high CG content in the coding sequences, nucleotide arrangement of purine-purine and pyrimidine-pyrimidine, methylation of nucleotides, histone/histone like proteins, reverse gyrase, cations, etc., also provide thermal stability to genome. Strategies adopted at the level of DNA are naturally, though not universally, reflected in RNA in thermophiles. Increased purine load (particularly of adenine), preferential codon usage, post-transcriptional modifications etc. provide thermal stability. All these factors may differ from taxa to taxa as no single or all the factors together can be universally attributed for providing thermal stability to nucleic acids.