Charity advertising has become diversified for more than twenty years. Previous research focused on charity advertising in non-profit organization (NPO) contexts. However not only NPOs but also corporations sponsor charity ads. As one of popular emotional appeals, guilt appeals are used to promote charitable giving. This study compares three types of advertising sponsor including NPO, corporation, and mixed type with sponsor-charity fit on the effects of guilt appeal in charity advertising. The present study employs an experimental design to investigate the effects of the guilt appeals (guilt appeals vs. non-guilt appeals), type of advertising sponsor (NPO vs. corporation vs. mixed) and sponsor-charity fit (high fit vs. low fit) in charity advertising effectiveness. Mixed type is defined as brand-cause alliance or cause-related marketing. A 2x3x2 factorial design is conducted. Twelve different scenarios are established and the ad effects are measured by attitudes toward the ad, purchase intentions, and attitudes toward the ad sponsor. Does guilt work with all types of sponsors? Results of the experiment indicate an interaction between type of advertising sponsor and guilt appeals. The guilt appeals are more effective when the NPO is the advertising sponsor or when the company frames the charity ad as CRM. However, the non-guilt appeals are more effective than the guilt appeals when a corporation is the ad sponsor. Guilt appeals are found to backfire under the two following circumstances: (1) when a corporation is the ad sponsor with a high fit between sponsor and charity, or (2) when mixed type with low sponsor-charity fit is framed in the ad. According to these findings, this study suggests that marketers should choose appropriate advertising appeals while considering their role as advertising sponsor and the sponsor-charity fit.