The role of helminths in asthma and/or rhinitis and in allergic sensitization is still unclear. We assessed the relationship between Ascaris-specific IgE, respiratory symptoms and allergic sensitization in Bangladesh immigrants. 246 individuals were examined from 1996 to 2001. Serum total IgE, Ascaris IgE, specific IgE to inhalant allergens, skin prick tests (SPT) and parasitological evaluation of the stool were performed. Total serum IgE were significantly higher in Ascaris-IgE positive (> 0.35 kU/L) individuals (806.5 [409.0-1436.0] kU/L vs. 207.0 [127.0-332.5] kU/L; P < 0.0001) and in subjects with respiratory symptoms (413.0 [239.0-1096.0] kU/L vs. 259.5 [147.0-387.0] kU/L), (P < 0.0001), but not in SPT positive subjects (413.0 [179.0-894.0] kU/L vs. 404.6 [305.0-1201.0] kU/L (P = 0.5). Ascaris-specific IgE were detected in 48 subjects with respiratory symptoms (40.0%) and in 46 subjects without respiratory symptoms (36.5%) (P = 0.5). The SPT positivity was similar between Ascaris-IgE seropositive (38.2%) and Ascaris-IgE seronegative (38.1%) subjects (P = 0.9). Total IgE and length of stay in Italy correlated with SPT positivity (OR 5.6 [CI 95% 1.5-19.8], P = 0.007, and OR 1.5 [CI 95% 1.3-1.7], P< 0.0001), and with respiratory symptoms (OR 13.7 [CI 95% 3.0-62.4];, P = 0.0007, and OR 2.4 [CI 95% 1.9-3.0], P < 0.0001). Ascaris-IgE were negatively associated with SPT positivity (OR 0.3 [CI 95% 0.1-0.8], P = 0.02) and with respiratory symptoms (OR 0.1 [CI 95% 0.04-0.7], P = 0.01). Our findings favour the role of environmental factors in the development of respiratory symptoms in immigrants, irrespective of Ascaris-IgE.