Limited studies have evaluated the link between acculturation and health outcomes of within-country migrants. The objective of this study was to evaluate whether well-known acculturation surrogates were associated with obesity among Peruvian rural-to-urban migrants. We performed a cross-sectional survey, the PERU MIGRANT study, using single-stage random sampling. Evaluation included weight, height, and waist circumference (WC) as well as acculturation surrogates. Obesity was assessed using BMI and WC. Length of residence, age at migration, language proficiency, and language preferences (Spanish or Quechua) were assessed in logistic regression models to calculate odd ratios and 95% confidence intervals adjusting for potential confounders. A total of 589 rural-to-urban migrants were enrolled. The mean age was 47.8 (s.d.: 11.7, range: 30-92), and 280 (47.5%) were men. Obesity prevalence assessed using BMI was 30.4% among women and 10.7% among men (P 0.001), whereas abdominal obesity assessed using WC was 29.1% among women and 19.1% among men (P< 0.01). Obesity was associated with older age at first migration, language speaking proficiency, and language preferences. The association between obesity and acculturation surrogates is variable in this population. Thus, acculturation per se can explore positive channels associated with better health outcomes. The patterns shown in this report suggest a more complex association for these factors. © 2010 The Obesity Society.