Background. Small-scale poultry production has the potential to increase animal-source food consumption, improve household income, and reduce food insecurity. Objective. To assess the impact of a chicken Newcastle disease vaccination program on consumption of chicken and eggs among women and children, income, and food insecurity in rural Tanzanian households. Methods. Comparisons were made between house- holds from three project villages, which participated in a Newcastle disease vaccination program for chickens, and three control villages, which did not participate. Household interviews were done with mothers from a random sample in March 2008 (237 households) and March 2009 (261 households). Results. After the first year of vaccinations (three rounds), project households kept significantly more chickens and tended to be more food secure than con- trol households. Mothers from project households ate significantly more eggs than their counterparts in con- trol households. A similar trend was observed among children. In 2009, fewer chickens were vaccinated in the project villages than in 2008, and more chickens were independently vaccinated in the control villages. This cor- responded with an increase in ownership of chickens, a reduction in food insecurity, and improved consumption of eggs in control villages, whereas chicken ownership and egg consumption decreased and food insecurity remained relatively stable in project villages. We saw no differences between project and control villages in income earned Danielle Knueppel, Montague Demment, and Lucia Kaiser are affiliated with the University of California, Davis, Cali- fornia, USA; Carol Cardona is affiliated with the College of Veterinary Medicine, University of Minnesota, St. Paul, Min- nesota, USA; Peter Msoffe is affiliated with the Department of Veterinary Medicine and Public Health at the Sokoine University of Agriculture, Morogoro, Tanzania. Please direct queries to the corresponding author, Danielle Knueppel, at: University of California, Davis, Department of Nutrition, Davis CA 95616, USA; e-mail: dmknueppel@ ucdavis.edu. 436 from chicken and egg sales. Conclusions. Our findings suggest that an increase in chicken Newcastle disease vaccination can lead to an increase in ownership of chickens and egg consumption and may also have an effect on reducing household food insecurity.