diff --git a/src/renderer/index.html b/src/renderer/index.html
index 4250979..3b55b14 100644
--- a/src/renderer/index.html
+++ b/src/renderer/index.html
@@ -89,6 +89,16 @@
   </div>
 </div>
 
+<div id="rename-conflict-modal" class="modal-overlay" style="display:none;">
+  <div class="modal-box">
+    <p class="modal-msg">변경할 이름의 파일이 이미 존재합니다.</p>
+    <ul id="rename-conflict-list" class="modal-conflict-list"></ul>
+    <div class="modal-actions">
+      <button id="rename-conflict-close" class="btn btn-ghost">닫기</button>
+    </div>
+  </div>
+</div>
+
 <div id="move-error-modal" class="modal-overlay" style="display:none;">
   <div class="modal-box">
     <p class="modal-msg">새로운 이름의 파일도 존재합니다.</p>
diff --git a/src/renderer/renderer.js b/src/renderer/renderer.js
index cb37057..3494466 100644
--- a/src/renderer/renderer.js
+++ b/src/renderer/renderer.js
@@ -36,7 +36,10 @@ const moveDigitsInput   = document.getElementById('move-digits');
 const moveCancelBtn     = document.getElementById('move-cancel');
 const moveConfirmBtn    = document.getElementById('move-confirm');
 const moveErrorModal    = document.getElementById('move-error-modal');
-const moveErrorCloseBtn = document.getElementById('move-error-close');
+const moveErrorCloseBtn        = document.getElementById('move-error-close');
+const renameConflictModal      = document.getElementById('rename-conflict-modal');
+const renameConflictCloseBtn   = document.getElementById('rename-conflict-close');
+const renameConflictList       = document.getElementById('rename-conflict-list');
 
 // ── 핸들러 초기화 ─────────────────────────────────
 const callbacks = {
@@ -248,18 +251,46 @@ function updatePreview() {
 }
 
 // ── 이름 변경 ────────────────────────────────────
+renameConflictCloseBtn.addEventListener('click', () => {
+  renameConflictModal.style.display = 'none';
+});
+
 async function doRename() {
   if (!state.files.length || !state.currentFolder) return;
   const prefix = inputPrefix.value.trim() || 'photo';
   const digits = Math.max(1, Math.min(6, parseInt(inputDigits.value) || 3));
 
-  const examples = state.files.slice(0, 3).map((f, i) => {
+  const selectedArr   = [...state.selectedIdxs].sort((a, b) => a - b);
+  const filesToRename = selectedArr.length > 0
+    ? selectedArr.map(i => state.files[i]).filter(Boolean)
+    : state.files;
+
+  if (!filesToRename.length) return;
+
+  // 선택된 파일이 있으면 변경될 이름이 미선택 파일 이름과 충돌하는지 확인
+  if (selectedArr.length > 0) {
+    const unselectedNames = new Set(
+      state.files.filter((_, i) => !state.selectedIdxs.has(i)).map(f => f.name)
+    );
+    const newNames = filesToRename.map((f, i) => {
+      const ext = f.name.split('.').pop().toLowerCase();
+      return `${prefix}_${String(i + 1).padStart(digits, '0')}.${ext}`;
+    });
+    const conflicting = newNames.filter(n => unselectedNames.has(n));
+    if (conflicting.length) {
+      renameConflictList.innerHTML = conflicting.map(n => `<li>${n}</li>`).join('');
+      renameConflictModal.style.display = 'flex';
+      return;
+    }
+  }
+
+  const examples = filesToRename.slice(0, 3).map((f, i) => {
     const ext = f.name.split('.').pop().toLowerCase();
     return `${f.name}  →  ${prefix}_${String(i + 1).padStart(digits, '0')}.${ext}`;
   }).join('\n');
-  const more = state.files.length > 3 ? `\n... 외 ${state.files.length - 3}개` : '';
+  const more = filesToRename.length > 3 ? `\n... 외 ${filesToRename.length - 3}개` : '';
 
-  if (!confirm(`📂 ${state.files.length}개 파일을 이름 변경합니다:\n\n${examples}${more}\n\n계속하시겠습니까?`)) return;
+  if (!confirm(`📂 ${filesToRename.length}개 파일을 이름 변경합니다:\n\n${examples}${more}\n\n계속하시겠습니까?`)) return;
 
   showLoading('파일 이름 변경 중...');
   setStatus('이름 변경 중...', false);
@@ -267,7 +298,7 @@ async function doRename() {
   try {
     const result = await window.api.renameFiles({
       folderPath: state.currentFolder,
-      files: state.files,
+      files: filesToRename,
       prefix,
       digits,
     });
diff --git a/src/renderer/style.css b/src/renderer/style.css
index f31dba0..bbf316d 100644
--- a/src/renderer/style.css
+++ b/src/renderer/style.css
@@ -517,6 +517,17 @@ footer span { font-size: 11px; color: var(--muted); }
 }
 .modal-fields input[type="number"] { width: 70px; text-align: center; }
 .modal-fields input:focus { border-color: var(--accent); }
+.modal-conflict-list {
+  list-style: none;
+  display: flex; flex-direction: column; gap: 4px;
+  max-height: 160px; overflow-y: auto;
+  background: var(--card); border: 1px solid var(--border);
+  border-radius: 8px; padding: 8px 12px;
+}
+.modal-conflict-list li {
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 12px; color: var(--warning);
+}
 .modal-actions {
   display: flex; justify-content: flex-end; gap: 10px;
 }