Marriage between cousins is a predictor of poor birth outcomes because it poses a high risk of replicating harmful recessive genes in the offspring [1]. However, as an offshoot of arrangedmarriage, this cultural practice is prevalent in many countries, including Pakistan. As a prevailing cultural norm, messages about the reproductive health costs of consanguinity are largely undermined and awareness among the affected population is low [2]. The present study analyzed data from a nationally representative sample from the Pakistan Demographic and Health Survey 2006–2007 [3]. The study included 5724 ever-married women of reproductive age (15–49 years) who delivered their last child during the five years immediately preceding the survey. For adverse birth outcomes, two dependent variables were used: neonatal death (death of a child during the firstmonth of life) and small-size birth (SSB) (neonatal birthweight less than or equal to 2500 g or neonatal size recorded as either “very small” or “smaller than average,” used as a proxy if birth weight had not been recorded). Multivariate logistic regression analysis was applied to estimate the independent effect of consanguinity on adverse birth outcomes using SPSS version 17 (SPSS Inc, Chicago, IL, USA). The retrospective nature of the study rendered it exempt from requiring informed consent or ethical approval.