Using panel data of three rounds collected from 12 districts in Tigray, this study assesses the impact of Ethiopia s Productive Safety Net Program (PSNP) on the probability of adoption of modern fertilizer and intensity of its use by rural farm households. We employ the control function approach to identify the impact. Results show that membership in the PSNP has a positive impact on the probability of adopting modern fertilizer but not on the amount of fertilizer that farm households use. This result may indicate that the PSNP is contributing to investments by farmers which may lead to achieving food security and enhanced productivity of poor farm households. Acknowledgement : The authors are grateful to the Norwegian Project for Capacity Development in Higher Education and Research for Development (NORHED) for funding this work through the Climate Smart Natural Resource Management and Policy (CLISNARP) project. We are also thankful to Mesfin Tilahun for the useful comments we got from him on this work.