Thalidomide has antiangiogenic properties and was found to be effective in patients with multiple myeloma (MM) when used in the setting of posttransplantation relapse. We have now analyzed risk factors associated with development of deep vein thrombosis (DVT) in a cohort of 535 patients treated with thalidomide with cytotoxic chemotherapy (VAD [vincristine/doxorubicin/dexamethasone], CAD [cyclophosphamide/doxorubicin/dexamethasone], DCEP [dexamethasone/cyclophosphamide/etoposide/cisplatin], or DT-PACE [dexamethasone/thalidomide/cisplatin/doxorubicin/cyclophosphamide/etoposide] or without cytotoxic chemotherapy (thalidomide and dexamethasone only). A total of 82 patients developed DVT, and the frequency was affected by a number of baseline characteristics. On multivariate analysis, the combination of thalidomide with chemotherapy including doxorubicin was associated with the highest odds ratio (OR) for DVT (4.3; P < or = 0.001); in addition, newly diagnosed disease (OR, 2.5; P = 0.001) and chromosome 11 abnormality (OR, 1.8; P = 0.048) were also independent predictors for DVT. With a median follow-up of 2.9 years, survival was inferior in patients with chromosome 13 abnormalities (P = 0.001), age > 60 years (P = 0.001), lactate dehydrogenase level > or = 190 IU/L (P = 0.002), and creatinine level > or = 2 mg/dL (P < 0.001). However, the development of DVT did not adversely affect survival when examined as a time-dependent variable and adjusted for standard risk features (hazard ratio, 0.8; P = 0.162).