© 2016, Springer Science+Business Media New York. What effect does the ratification of International Labour Organization (ILO) conventions have on labor rights? Despite the prominent role of ILO conventions in establishing international labor standards, surprisingly little is known about whether these conventions have any significant effect on the rights they seek to improve. This article provides a comprehensive assessment of the possible impact that seven fundamental ILO conventions have on labor rights in ratifying countries. Results from the data analysis for the period 1981–2011 suggest that the ratification of core ILO conventions is negatively associated with the level of respect for worker rights. One major implication of our findings is that while the adoption of core ILO conventions is crucial in recognizing primary rights of workers, they might paradoxically serve to undercut those rights.