Background: The aim was to investigate prognostic relevance of history of allergy in subjects with unstable angina treated with coronary angioplasty. METHODS: Fifty-seven consecutive patients with unstable angina who underwent coronary angioplasty were enrolled in the study and were divided into two groups: those with a history of allergy (Group A, N=15); and controls (Group C, N=42). Major adverse cardiac events were recorded over a six-month follow-up period. Patients with primary or unsuccessful angioplasty and patients treated with drug eluting stent were excluded from the study. RESULTS: Group A patients (history of allergy) showed a 46.67% incidence of major adverse cardiac events at six-month follow-up (vs. 9.52% Group C, p<0.01): results remained significant even in a multiple Cox regression analysis (hazard ratio 7.17, 95% CI 1.71-29.98, p<0.01). CONCLUSION: History of allergy is an independent predictor of major adverse cardiac events after coronary angioplasty in a six-month follow-up period in unstable angina