The primary object of this thesis is to use various content analysis tests to determine the direction and degree of bias and imbalance in the election communication of media organisations generally representative of television and newspaper coverage of the 1990 General Election. To this end, investigation faced a number of theoretical, methodological and empirical tasks. In terms of theory, the empirical analysis had to be defined within the context of political and mass media systems, and be placed within a broader comparative framework of political communication. The methodology was developed to test for imbalance (in the amount of news) and bias (in the orientation of news) separately. The results were combined to see whether an approximation of the advantage in election communication enjoyed by the incumbent party could be determined, and whether any imbalance (usually toward the incumbents) was reflected in bias in news content (where the media exert a stronger control).