BACKGROUND: Fat intake has been associated with respiratory diseases, with conflicting results. OBJECTIVE: We studied the association between asthma and rhinitis with dietary fats, and their food sources in an Italian population. METHODS: Clinical and nutritional information was collected for 871 subjects (aged 20-84) from the population-based multi-case-control study Genes Environment Interaction in Respiratory Diseases (GEIRD): 145 with current asthma (CA), 77 with past asthma (PA), 305 with rhinitis and 344 controls. Food intake was collected using the EPIC (European Investigation into Cancer and Nutrition) Food Frequency Questionnaire. The associations between fats and respiratory diseases were estimated by multinomial models. Fats and their dietary sources were analysed both as continuous variables and as quartiles. RESULTS: Monounsaturated fatty acids and oleic acid were associated with a reduced risk of CA in both continuous (RRR = 0.68, 95%CI: 0.48; 0.96; RRR = 0.69; 95%CI: 0.49; 0.97, per 10 g, respectively) and per-quartile analyses (p for trend = 0.028 and 0.024, respectively). Olive oil was associated with a decreased risk of CA (RRR = 0.80; 95%CI: 0.65; 0.98 per 10 g). An increased risk of rhinitis was associated with moderate total fat and SFA intake. CONCLUSIONS: High dietary intakes of oleic acid and of olive oil are associated with a lower risk of asthma but not of rhinitis.