Raltegravir, as the first HIV integrase inhibitor, has been used and prospectively monitored since 2010 in our HIV outpatient centre, where over 1,200 patients are monitored. The aim of our report is to perform an interim assessment of the background, the safety profile and the clinical-laboratory monitoring of all patients treated with a combination antiretroviral therapy (cART) including raltegravir, for at least 12 months. In all, 109 pretreated patients started a raltegravir-containing cART when aged 44.8 plus or minus 19.2 years, with a history of HIV infection lasting 13.4 plus or minus 9.7 years. All subjects were monitored for at least 12 months (mean 17.2 plus or minus 10.3 months). In the vast majority of cases (93 of 109: 85.3%), multiple (3-16) prior cART changes prompted raltegravir introduction in advanced-salvage lines: 72 of 109 (66.1%) patients had even developed a concurrent triple-class resistance to anti-HIV compounds. The most frequent companion antiretroviral agents were: darunavir/ritonavir (75 cases), maraviroc (47 subjects), and etravirine (38 cases). The most common underlying conditions were: AIDS (46 patients), liver cirrhosis (31 cases), AIDS-related or other malignancies (23 cases), and major cardio-cerebro-vascular events (18 cases). A chronic HCV and HBV hepatitis were of concern in 48 and 23 patients, respectively. The adjunct of raltegravir favourably affected all clinical-laboratory markers of HIV disease progression, and those of the broad spectrum of comorbidities, except for two patients who failed the raltegravir-containing cART due to insufficient adherence. Despite the already compromised clinical situation, a minority of subjects experienced mild-transient clinical-laboratory untoward events possibly attributable to raltegravir, such that no patients discontinued raltegravir during the observation period. Only three AIDS-defining conditions became apparent during raltegravir-based cART; chemotherapy and/or radiotherapy cycles were performed as scheduled in patients suffering from cancer; chronic hepatitis B and C progressed to liver cirrhosis and/or hepatocarcinoma in only 2 and 6 patients. Otherwise, treatment with pegylated interferon-ribavirin became feasible in 25 patients of 48 with chronic HCV. During raltegravir-containing cART, neither autoimmune disorders nor novel malignancies were diagnosed. Only mild-transient gastrointestinal disorders, fatigue, dizziness, insomnia and cutaneous rash were reported, although their relationship with the study drug was difficult to assess due to multiple comorbidities and polypharmacy. Abnormal liver function testings were observed in 57 patients (52.3%), all suffering from concurrent hepato-biliary disorders. Significant increases in serum lipids and/or lipase levels versus baseline values were never registered: serum lipid levels significantly improved after raltegravir introduction. Our experience with raltegravir underlines its excellent efficacy and safety profile, which exploits a novel mechanism of action, and displays no cross-resistance with any other antiretroviral. A progressively extended prescription in naive patients and early cART lines will allow the therapeutic potential of raltegravir to be exploited.