In order to analyze the clinical relevance of the pharmacokinetic interactions between vinblastine and antiretrovirals described in literature, we evaluated all HIV-infected patients with Hodgkin's lymphoma treated with vinblastine-containing regimens and combination antiretroviral therapy, in a single clinical center. The use of protease inhibitors was independently associated with WHO grade III-IV neutropenia. Moreover, an inverse correlation between dosage of ritonavir and mean nadir neutrophil count was found. The concomitant administration of vinblastine-containing chemotherapy regimens with protease inhibitors can lead to higher levels of neutropenia than those of different classes of drugs such as nonnucleoside reverse transcriptase inhibitors or integrase inhibitors.