The number of charges of unfair labor practices filed with the National Labor Relations Board has grown steadily. This article analyzes the incidence of case filings since 1952 as a function of economic variables, such as the unemployment rate and changes in the price level; the number of strikes and representation petitions filed, since both tend to produce litigation; and aspects of the Board's administrative processes that tend to encourage or discourage case filings, such as the extent of delay. The study finds that, contrary to the assumptions of national labor policy, the Board's activities themselves may be an important determinant of union and employer demands for regulatory intervention. The model proves less satisfactory, however, in explaining the filing behavior of individuals, suggesting that workers have unrealistic expectations about the protection offered them by the National Labor Relations Act.