Background and Objective: Studies from Europe suggest that immigrant children tend to attend hospital emergency departments (ED) more frequently and more often for less-urgent conditions than non-immigrant children. In Portugal evidence on healthcare utilisation, particularly for immigrant children, is scarce. Objectives: To compare utilisation of ED in the Health trajectories of Immigrant Children (CRIAS) cohort, in 2019 and 2020. Methods: Data from the 1st and 2nd waves of the CRIAS cohort were analysed. The cohort was set up in 2019 in Amadora municipality, in the Metropolitan Area of Lisbon; 420 children (51.6% immigrant) born in 2015 were recruited. Results: In 2019, 1.3 times more immigrant children visited ED (53.5%vs40.4%; p=0.010); 19% of immigrant versus 16% of non-immigrant (p=0.006) children were frequent users. Clinical priority was low/moderate in about 90% of visits in both groups. Self-referral occurred in 89.4% of all visits, referrals to ED by an health professional were 3 times more likely among non-immigrant children (13.7%vs4.5%). Inpatient admissions occurred in 2 % of visits, with 2 times more admissions of immigrant children. Difficulties in accessing primary healthcare (48.4%) and perceived urgency (23.2%) were the main reasons given by the parents to attend ED; parents of immigrant children reported 1.3 times more difficulties in accessing primary care. In 2020, a marked reduction in Ed visits were observed: 28.9% immigrant versus 26.7% non-immigrant used ED. There was a 2-fold increase in visits referred by a health professional mainly from the NHS helpline, yet immigrant children continued to use it less frequently (10.3%vs3.8%). Conclusions: Compared with non-immigrant children, Immigrant children have a higher use of ED with their parents reporting more difficulties in accessing primary healthcare. Results suggest inappropriate use of ED by all children. Strengthening primary care and improving health literacy can address such inappropriate use of ED.