BACKGROUND Asthma still represents a cause of death and hospital admissions worldwide. Our study aimed at analyzing the trend of Emergency Room (ER) asthma admissions in Northeast Italy in order to investigate the relevance of specific patient-related determinants and environmental triggers (pollens, mold spores, and pollutants). METHODS Retrospective data from admissions for asthma exacerbations registered between the years 2013 and 2015 in two main ERs in Northeast Italy were collected. Data about patients' age, sex and nationality were recorded. Classification of disease severity followed the current Italian ER triage scoring system (white: no need for emergency treatment; green: need for fast treatment; yellow: severe condition; red: life-threatening condition). Data on pollen/mold spore counts and pollutants were analyzed. RESULTS Overall, 1745 ​ER admissions for asthma were registered, with a persistent and significant increase year by year. A slight prevalence of females and patients over 50 years old was observed. Immigrants accounted for 32%, 36% and 26% of admissions respectively in 2013, 2014 and 2015. The prevalence of immigrants' admissions was significantly higher when comparing the relative ratio of immigrant populations/Italian nationals (p ​< ​0.05). The admissions were coded as follows: white, 6.30%; green, 35.36%; yellow, 39.37%; red, 18.97%. People aged ≥50 years were more frequently admitted with a red code, but the trend was not statistically significant (p ​= ​0,0815). By contrast, amongst immigrants there was a higher prevalence of white and green codes observed in comparison with Italian nationals. Grass pollen peak and PM10 high levels represented environmental determinants of ER admissions increase. CONCLUSIONS The increasing rate of asthma-related ER admissions highlights the need for implementing asthma control strategies. Investigating the traits of patients referring to ER for asthma exacerbations, as well as environmental-related determinants, may help in identifying at-risk individuals and in orienting preventive strategies accordingly. Immigrants represent the most vulnerable sub-population, and their potential difficulties in accessing treatments and health services should be specifically addressed. Overall, implementing patient education in order to improve treatment adherence, as well as providing an asthma action plan to every asthmatic patient, continue to be the most urgent needs.