The television broadcasting industry is of crucial economic and social importance. Traditionally, this industry has been dominated by free-to-air TV (FTV) but due to technological progress, subscription-based pay TV (PTV) has emerged as a competing business model. A key question for the PTV broadcasters is whether to air commercials in addition to charging subscription fees. Based on a theoretical model of asymmetric competition between a PTV and an FTV broadcaster, we examine the effects of placing PTV advertising on broadcaster market strategies, viewer demands, broadcaster profits and consumer surplus. We find that introducing advertising on PTV can induce a higher viewer demand on this channel but a lower viewer demand on the FTV channel. Surprisingly, consumers can benefit through the introduction of advertising in PTV and broadcaster profits can increase if the viewer disutility of advertising is sufficiently large. Our study provides an analytical framework for choosing and implementing an optimal PTV strategy when an FTV competitor preexists in the market. Furthermore, our study derives implications for policymakers and regulatory authorities by showing that additional PTV advertising is not necessarily socially undesirable due to the strategic market reactions.