To determine the maximum tolerated doses (MTDs) and dose limiting toxicities (DLTs) of gemcitabine (GEM), docetaxel (DOC) and carboplatin (CARBO) combination.A total of 33 previously untreated HER-2 negative patients with stage IIIB-IV breast cancer received escalated doses of GEM, DOC and CARBO all given sequentially on day 1 every 2 weeks. Twenty-three patients (70%) had previously received adjuvant or neoadjuvant chemotherapy.The recommended MTDs are GEM 1,500 mg/m(2), DOC 50 mg/m(2) and CARBO 3AUC. Seven dose levels were evaluated and neutropenia was the primary dose-limiting event. Of 319 chemotherapy cycles delivered, grade 3-4 neutropenia occurred in 13.5% of them with two cases of febrile neutropenia. Diarrhea and asthenia were the most common non-hematological toxicities. Three (16%) complete and 6 (32%) partial responses were observed among 19 patients with measurable disease.The biweekly administration of GEM, DOC and CARBO is a well-tolerated regimen which merits further evaluation.