PURPOSE: To investigate temporal changes in multiparametric MRI (mpMRI) findings following lesion-targeted focal therapy with microwave tissue coagulation (MTC) for localized prostate cancer (PCa). METHODS: This retrospective study included 33 patients (34 procedures) with localized PCa who underwent lesion-targeted focal therapy with MTC between June 2019 and March 2024. Post-treatment mpMRI, including T2-weighted imaging (T2WI), T1-weighted imaging (T1WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced MRI (DCE-MRI), was evaluated by three radiologists to analyze signal changes and enhancement patterns in the treated area. Inter-reader agreement for each MRI sequence was also assessed. RESULTS: The median PSA reduction following treatment was 82 % (range, 18 %-99 %). The average post-treatment observation period was 16.5 months (range, 2.8-51.6 months), with a total of 97 post-treatment mpMRI scans conducted. In the early post-treatment period (3-6 months), the treated area exhibited heterogeneous hypointensity with a hypointense rim on T2WI, hyperintensity or isointensity on T1WI, and heterogeneous mixed signal intensity on DWI. Over time, these patterns diminished, with all lesions demonstrating hypointensity on T2WI, T1WI, and DWI by 17, 28, and 22 months, respectively. On DCE-MRI, rim enhancement predominated in the early post-treatment period, while all lesions showed no enhancement during later follow-up. CONCLUSION: After lesion-targeted focal therapy with MTC for localized PCa, MRI findings in the treated area exhibited dynamic changes during the early post-treatment period, ultimately stabilizing as hypointensity across all sequences and no enhancement during late follow-up.