During the period September 1983 through May 1985, Candida parapsilosis was isolated from intravascular sites (blood or vascular catheter tips) in 12 patients at a pediatric hospital. Of 205 patients with cultures of any site positive for Candida species, 32 (16%) had cultures positive for C. parapsilosis. In contrast, of 23 patients with intravascular cultures positive for Candida species, 12 (51%) had cultures positive for C. parapsilosis (P less than 0.001, Fisher's exact test). The 12 patients with intravascular cultures positive for C. parapsilosis were more likely to have received central venous nutrition therapy (10 of 12 versus 7 of 23; P less than 0.01, Mantel-Haenzel chi-square test) and had a longer duration of exposure to blood pressure transducers (P less than 0.08, paired t test) than the 23 ward- and age-matched controls. C. parapsilosis was isolated from 11 (32%) of 34 in-use and stored blood pressure transducers. After ethylene oxide sterilization of blood pressure transducers was begun, in-use pressure transducers showed no growth of C. parapsilosis. This study emphasizes the role of C. parapsilosis as a nosocomial pathogen associated with invasive devices and parenteral nutrition; it also emphasizes the importance of adhering to recommended procedures for sterilizing blood pressure transducers.