Soft tissue sarcomas are malignant neoplasms originating from mesenchymal cells. In cats, there are two groups: inoculation site-associated sarcomas (ISSs) and non-inoculation site-associated sarcomas (NISSs). The aim of this study was to investigate the immunoexpression of metalloproteinases (MMPs) 2 and 9, tissue inhibitors (TIMPs) 1 and 2, and the main molecules related to angiogenesis and vascular count in both sarcoma groups; compare their expression; and evaluate their association with angiogenesis. Both tumor groups expressed all the molecules evaluated. A positive correlation was detected between MMP-2 and angiogenic factors in both ISSs and NISSs. MMP-9 expression correlated positively with MMP-2 in both groups. TIMP-1 correlated with both MMP and with angiogenic factors in ISS. Fibroblast growth factor receptor 2 (FGFR-2) expression was higher in NISS. Studying the pathways that regulate angiogenesis in these neoplasms is crucial for identifying ways to intervene and limit neoplastic progression, thereby developing new therapeutic approaches.