Aims of this study were to determine the toxicity profile and the recommended dose of pegylated liposomal doxorubicin (Caelyx) in combination with topotecan in patients with advanced malignancies. Caelyx: 35 (DLI) or 40 (DLII) mg/m2/d1 was followed by 0.5 mg/m2/d topotecan daily for 5 days, every 4 weeks. Twenty-three patients received a total of 82 cycles. At DLII, 2/6 patients experienced dose-limiting toxicity consisting of grade 4 neutropenia lasting for more than 7 days and febrile neutropenia. At DLI, 4/18 and 2/18 patients presented febrile neutropenia and grade 4 sustained neutropenia, respectively. Non-hematological toxicities were mild to moderate. One patient with ovarian cancer presented a complete response. The hematological toxicity was a dose limiting factor that led to the recommended dose of 35 mg/m2 Caelyx on day 1 with 0.5 mg/m2/d topotecan on days 1-5. This study results suggest that alternative schedules of this combination are required.