We sought to determine factors associated with opportunistic infections (OI) in infliximab-treated patients. A retrospective study cohort (1999-2004) was examined. Nine OI were diagnosed in 94 infliximab-treated patients: tuberculosis (four), visceral leishmaniasis (one), pyogenic muscular abscess (one Salmonella spp. and one Streptococcus pneumoniae), and two viral infections (hepatitis B virus [HBV] and zoster ophthalmicus). The risk for OI was significantly higher in the first year of treatment (odds ratio [OR] 8; 95% confidence interval [CI] 2-50). Previous treatment with more than two immunosuppressive drugs was the only factor related to OI (OR 8.686; 95% CI 1.889-39.943). We identified the subset of patients treated with infliximab who had a higher risk for OI. The screening of latent infections is key to diminishing the incidence of these infections.