Human migration and its economic, social, and demographic effects can lead to health consequences for individuals and populations. In the present study, we estimated differences in health status between migrant (those who had come to Wrocław at the age of > or =16 years) and nonmigrant (those who had lived in Wrocław since birth or had come with their parents) inhabitants of Wrocław, Poland. Three hundred and sixty seven males and 496 females aged 40 and 50 underwent medical examination, and were asked to fill out a questionnaire comprising social, demographic, and life style information. Health status was assessed by blood pressure, heart rate, fasting lipid profile, glucose, height, and measures of fatness (BMI, WHR, sum of skinfolds). Comparisons were made based on Borkan's and Norris's profiles. Student's t-test showed significant differences in diastolic blood pressure, heart rate, total cholesterol, and glucose levels between two groups of males, in favor of migrants. Male migrants were also significantly taller than their peers born in Wrocław. In females, migrants had significantly lower blood pressure and heart rate than nonmigrants. In interpreting the results two possible, not mutually exclusive, mechanisms are proposed: selective spatial mobility, and changes toward healthier life style as an adaptation to new urban environment.