We investigated the clinical relevance of doubling time (DT) of serum laboratory data obtained in routine clinical examination of patients with primary bone and soft tissue tumors, in comparison with major clinical and pathological parameters (age at presentation, sex, tumor size, location, clinical stage and histologic grade) by uni‐ and multivariate analyses. In 64 patients with primary bone and soft tissue tumors (primary bone tumors: 39, primary soft tissue tumors: 25) and 68 cancer patients, the pretreatment DT values of serum C‐reactive protein (CRP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), calcium (Ca), phosphate (P) levels were measured, as well as the erythrocyte sedimentation rate (ESR: mm/60 min); these values were then compared with overall survival, local recurrence‐free survival and metastasis‐free survival. Only DT of CRP and ALP (CRP‐DT, ALP‐DT) were found to be correlated with disease outcome in patients with primary bone and soft tissue tumors. In cancer patients, only CRP‐DT showed a relation with clinical stage and histologic grade, but the ALP‐DT in patients with bone metastasis was significantly shorter than that in patients with metastases at other sites or in those with no metastasis. Among all tumor patients, those with bone metastasis showed the shortest ALP‐DT compared with those with lung, liver and brain metastasis. Univariate analysis showed that shorter CRP‐DT and ALP‐DT are associated with poor overall survival, and the development of local recurrence and metastasis. These findings suggest that pretreatment CRP‐ and ALP‐DT could be additional prognostic parameters for disease outcome in patients with primary malignant bone and soft tissue tumors. However, in multivariate analysis, only ALP‐DT, but not CRP‐DT, was an independent prognostic parameter for these disease outcomes.