Control of Chagas disease requires control of its triatomine vectors, which requires an understanding of the determinants of infestation. Twenty-seven household environmental characteristics in the town of Chalcatzingo, Morelos, were analyzed for association with infestation by Triatoma pallidipennis, the predominant local vector. Data were obtained through timed household searches for triatomines and surveys that characterized intradomicile and peridomicile environments. Of the households surveyed, 28.4% were infested by T. pallidipennis. Cross-sectional multivariate logistic regression analyses were performed that regressed infestation on environmental variables. Of the 530 households in the town, 84% had sufficient data to be included. Adobe walls, agricultural products, junk piles, lack of bednets, and number of rabbits were significantly associated with intradomiciliary infestation. Junk piles and numbers of dogs, cats, and rabbits were significantly associated with peridomiciliary infestation. Junk piles, agricultural products, and numbers of cats, rabbits, and birds were significantly associated with overall infestation. Unexpectedly, presence of stone piles was not associated with infestation. The results of this study provide information for designing Chagas disease control programs in rural Mexican areas infested by T. pallidipennis.