Objective. To summarize the systematic development of docetaxel as a new and effective treatment option for advanced non-small cell lung cancer (NSCLC) and breast cancer patients, and to discuss the physical and chemical stability, compatibility with drugs commonly used in cancer patients, and administration issues with the new docetaxel formulation. Data Sources. A MEDLINE search was conducted using carboplatin, cisplatin, compatibility, docetaxel, doxorubicin, metastatic breast cancer (MBC), NSCLC, and stability as search terms. Reference lists, bibliographies of pertinent articles, and abstracts from the American Society of Clinical Oncology and the European Society for Medical Oncology annual meetings were also identified and reviewed. Information related to the new docetaxel formulation was obtained from the manufacturer. The clinical literature was reviewed and analyzed. Data Synthesis. Docetaxel has recently emerged as an active agent in the treatment of advanced NSCLC and MBC. Results of phase II and III studies of single-agent docetaxel and docetaxel combinations, both as first- and second-line therapy, have produced impressive response rates and improved survival times compared with current standards of care. Docetaxel has a unique toxicity profile that includes hypersensitivity reactions, skin toxicities, and fluid retention. Because docetaxel's toxicity profile differs from that of the platinum analogs and the anthracyclines, combinations with these agents for NSCLC and MBC are well tolerated. Docetaxel was recently reformulated, allowing for improved stability, shelf-life, and storage requirements. Compatibility studies of docetaxel with 81 commonly used drugs in cancer patients were recently reported, showing that docetaxel is compatible with all but three drugs studied—amphotericin B, nalbuphine hydrochloride, and methylprednisolone sodium succinate—when administered as Y-site injections into existing intravenous lines. With the increasing use of this agent, the new docetaxel formulation and compatibility data should facilitate ease of administration.