Aim: This study examined the clinical status and socio-demographic conditions of children with type 1 diabetes at baseline and after three years of treatment, comparing those born to immigrant parents and Swedish parents. Methods: This observational nationwide population-based cohort study used prospectively collected registry data from Swediabkids, the National Quality Registry for Paediatric Diabetes in Sweden from 2000 to 2010. Of the 13 415 children with type 1 diabetes, there were 879 born to immigrant parents. We selected three children born to Swedish parents from the same registry for each immigrant child matching them by gender, age and year of diabetes onset (n = 2627; with 10 control children missing probably due to the matching procedure). Results: Immigrant children had a higher median glycated haemoglobin level (HbA1c) than their Swedish peers, but there was no difference in the frequency of hypoglycaemia or ketoacidosis between the two cohorts. A linear regression model with HbA1c as a dependent variable showed that insulin units per kilogram of body weight were the main reason for inferior metabolic control. Conclusion: Children with type 1 diabetes born to immigrant parents had inferior metabolic control three years after disease onset compared to children with Swedish born parents. Social family support and educational coping programmes are needed to improve treatment outcomes in immigrants with diabetes.