Few studies on oncogenesis of chondrosarcoma (CS) are available in the literature. Our previously published experimental evidence suggests that while the C-propeptide of procollagen Iα1 (PC1CP), a component of cartilage, favors tumor progression, the C-propeptide of procollagen IIα1 (PC2CP) exerts antitumor properties. In this study, we analyzed expression of PC1CP and PC2CP by immunohistochemistry in a series of enchondromas and CS. Our retrospective series consisted of 88 cases, including 43 CSs, 34 enchondromas and 11 nontumor samples. Immunohistochemical staining for PC1CP and PC2CP was evaluated in the cytoplasm and in the extracellular matrix (ECM). Diffuse staining for PC1CP in ECM was significantly more frequent in tumor than in nontumor samples (32 % vs. 0 %; p = 0.03), and in CSs than in enchondromas (44 vs. 18 %; p = 0.02). ECM semiquantitative score was higher in tumors than in nontumor samples (p < 0.005) and higher in CSs than in enchondromas (p = 0.05). Staining for PC2CP in ECM was more frequently found in enchondromas than in CSs (59 vs. 33 %; p = 0.02). ECM semiquantitative score was higher in enchondromas than in CSs (p = 0.02). Diffuse staining for PC1CP in combination with absence of staining for PC2CP had 94 % specificity for CS but with a sensitivity of only 35 %. Expression of neither PC1CP nor PC2CP correlated with recurrence-free survival or occurrence of metastases. In conclusion, we show that the expression of PC1CP is higher and that of PC2CP lower in malignant cartilaginous tumors. These results support an oncogenic role of PC1CP and anti-oncogenic property of PC2CP in cartilaginous tumors.