To evaluate the presence of HIV-1 non-B subtypes in Sicily, we sequenced and genotyped HIV-1 PR and RT regions of the pol gene using plasma from 169 HIV-1-infected adult patients. All samples were obtained from a study of antiretroviral-associated resistance mutations resulting in virological failure during highly active antiretroviral therapy (HAART). Eight (4.7%) patients had the non-B HIV-1 subtype including some circulating recombinant forms (CRFs). All of these individuals acquired the infection by heterosexual transmission. The detection of HIV-1 non-B strains was significantly associated with younger age of HIV-1 acquisition. Our findings indicate, for the first time, the presence of HIV-1 non-B subtypes in Sicily in patients who experienced virological failure during HAART, and highlight the need for implementing a network for the epidemiological surveillance of HIV-1 subtypes in Southern Europe.