As docetaxel is known to have significant antineoplastic activity against breast and ovarian cancer, we explored its application as a peripheral blood stem cell mobilizing agent in 33 women with stage lll-IV ovarian carcinoma (n = 10) or stage ll-lV breast cancer (n = 23) who were in preparation for high-dose chemotherapy. Eleven patients had bone and/or bone marrow involvement with their disease. The median number of prior regimens received before mobilization was two (range 1-3). The three dose levels administered were 100 mg/m(2), 110 mg/m(2) and 120 mg/m(2). Patients received one dose of docetaxel in the outpatient setting followed by G-CSF (10 microg/kg/day) starting 4 days after docetaxel administration. Leukapheresis commenced when WBC >1.0 x 10(9)/l or when the WBC began to rise after reaching a nadir. Ninety-seven percent of patients began leukapheresis within 7-9 days after receiving docetaxel (range 7-10 days). The collection goal was >/=2 x 10(6) CD34(+) cells/kg. Twenty-seven (82%) patients reached this goal in a median of 2 leukapheresis days (range 1-3). No grade 2-4 nonhematologic toxicities were noted. Thirteen patients (55%) showed a WBC nadir >1.0 x 10(9)/l. None of the patients experienced neutropenic fever or required blood or platelet transfusion support. In conclusion, docetaxel + G-CSF is an effective, well-tolerated regimen for PBPC mobilization which can be safely administered in the outpatient setting with minimal toxicity.