RNA fingerprint analysis was carried out with different strains of Japanese encephalitis virus which were isolated from Japan, China, India and Sri Lanka. From the similarity ratios, a similarity matrix was worked out which yielded a dendrogram. Geographical proximity of the place of isolation did not contribute much to the similarity of the fingerprint of the strains, nor did temporal proximity. The Japanese Nakayama strain had greater similarity with the Asansol strain from West Bengal. However, another strain from West Bengal, the Bankura strain, showed marked difference. Similarly the Bhopal and Beijing (China) strains were relatively close to each other while the Japanese JaGAr15460 strain was nearer to the strain from Gorakhpur. Serial mouse passage of the Asansol strain did not change the fingerprint pattern drastically.