A Java applet, very efficient for interactively visualizing results of comparative sequence analysis in the VISTA format on the scale of whole chromosomes along with annotations. The user may select any genome as the reference or base, and display the level of conservation between this reference and the sequences of another species in a particular interval. A user can use default values for conservation cutoffs (X% over Y bp), or specify them. Conserved regions are highlighted under the curve, with different colors used for coding and noncoding sequences. The browser has a number of options, such as zoom, extraction of a region to be displayed, user-defined parameters for conservation level, and options for selecting sequence elements to study. VISTA Browser is realized as a dynamic web-interface synchronized with the central MySQL.