This paper analyzes the relationship between the firm characteristics and the extent of fixed-mobile convergence in the telecommunications industry. In recent years there has been a trend of convergence between fixed and mobile telecommunications services. Facing the convergence, telecommunication companies are in the different stage of FMC. Those differences in the extent of FMC may come from various internal and external factors of the firm. In this paper the effect of internal factors, specifically firm characteristics, is analyzed. The stage of fixed-mobile convergence is developed into 5-scale stage in terms of service offerings. 41 U.S. telecommunication companies are put on the appropriate stage according to the extent of offering fixed-mobile converged services. The extent of FMC of the firms and the firm characteristics including the firm size, industry tenure, and firm scope are analyzed with statistical methodology. The result shows that the firm size and firm’s product scope have significant impact on the extent of FMC.