Although novel therapeutic strategies, expected lifetime of patients with multiple primary tumors is still short. However early diagnose of solid tumors can improve survival. Espe-cially PET CT evaluation can be an important guide to detect second primary tumor. In hematological malignancies particularly in lymphomas and myeloma, in those solid tumors can be misdiagnosed as progression. So discrimination is more difficult in these cases. Therefore we planned to focus on diagnostic procedures, histological types, tumor sites and survival parameters as objec-tives of this study. Patients with two cancers with hematological malignancies and solid tumors or second hematological malignancy were enrolled. An exclusion criterion was treatment-associated hematological malignancies. For statistical analysis, the SPSS program was used. Writ-ten informed consent was taken from all patients. This study was reviewed and approved by local ethics committee. Fourty five patients were enrolled to study. Among these 45 cases of multiple primary malignan- cies, 20 of them were synchronous (44.4%) and 25 of them were metachronous (55.6 %) (p= 0.63). The most frequently diagnosed hematological malignancy in this double primary cancer study was Non-Hodgkin’s lymphoma (23 cases; 51.1%). During follow up, 22 of 45 patients died. Median interval between the diagnosis of two tumors was 11 months (95% CI: 1-168). 36 months survival was 65.5% (95% CI: 48. 0-78.4 months). New cancers can develop at the same time or after treatment of one cancer. The incidence of second primary cancers on patients with hematological malignancies is ex-pected to increase due to the better screening programs for early detection of malignancies as well as considerable improvement in their treatment, using novel imaging techniques and longer life expectancy.