diff --git a/src/main/java/com/cake/pop/domain/letter/controller/LetterController.java b/src/main/java/com/cake/pop/domain/letter/controller/LetterController.java
index 8b11d83..dd1431b 100644
--- a/src/main/java/com/cake/pop/domain/letter/controller/LetterController.java
+++ b/src/main/java/com/cake/pop/domain/letter/controller/LetterController.java
@@ -11,6 +11,7 @@
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
@@ -57,4 +58,9 @@ public ResponseEntity<List<SimpleLetterDto>> getStorages() {
         return ResponseEntity.ok(response);
     }
 
+    @PatchMapping("/{letterId}/report")
+    public ResponseEntity<Void> reportLetter(@PathVariable("letterId") Long letterId) {
+        letterService.reportLetter(letterId);
+        return ResponseEntity.ok().build();
+    }
 }
diff --git a/src/main/java/com/cake/pop/domain/letter/repository/LetterRepository.java b/src/main/java/com/cake/pop/domain/letter/repository/LetterRepository.java
index 79af9d4..2608a6a 100644
--- a/src/main/java/com/cake/pop/domain/letter/repository/LetterRepository.java
+++ b/src/main/java/com/cake/pop/domain/letter/repository/LetterRepository.java
@@ -16,15 +16,21 @@ public interface LetterRepository extends JpaRepository<Letter, Long> {
 
     List<Letter> findByMailbox(Mailbox mailbox);
 
-    @Query("SELECT l FROM Letter l JOIN FETCH l.mailbox WHERE l.id = :id")
-    Optional<Letter> findByIdWithMailbox(@Param("id") Long id);
+    List<Letter> findByMailboxAndStatus(Mailbox mailbox, com.cake.pop.entity.enums.Status status);
+
+    @Query("SELECT l FROM Letter l WHERE l.id = :id AND l.status = 'ACTIVE'")
+    Optional<Letter> findActiveById(@Param("id") Long id);
+
+    @Query("SELECT l FROM Letter l JOIN FETCH l.mailbox WHERE l.id = :id AND l.status = 'ACTIVE'")
+    Optional<Letter> findActiveByIdWithMailbox(@Param("id") Long id);
 
     default Letter getById(Long id) {
-        return findById(id).orElseThrow(() -> new RestApiException(LetterErrorCode.LETTER_NOT_FOUND));
+        return findActiveById(id)
+                .orElseThrow(() -> new RestApiException(LetterErrorCode.LETTER_NOT_FOUND));
     }
 
     default Letter getByIdWithMailbox(Long id) {
-        return findByIdWithMailbox(id)
+        return findActiveByIdWithMailbox(id)
                 .orElseThrow(() -> new RestApiException(LetterErrorCode.LETTER_NOT_FOUND));
     }
 }
diff --git a/src/main/java/com/cake/pop/domain/letter/service/LetterService.java b/src/main/java/com/cake/pop/domain/letter/service/LetterService.java
index f50e648..603fac4 100644
--- a/src/main/java/com/cake/pop/domain/letter/service/LetterService.java
+++ b/src/main/java/com/cake/pop/domain/letter/service/LetterService.java
@@ -14,10 +14,13 @@
 import com.cake.pop.entity.Storage;
 import com.cake.pop.entity.User;
 import com.cake.pop.entity.enums.Region;
+import com.cake.pop.entity.enums.Status;
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
+@Transactional(readOnly = true)
 @Service
 @RequiredArgsConstructor
 public class LetterService {
@@ -27,19 +30,19 @@ public class LetterService {
     private final StorageRepository storageRepository;
     private final UserRepository userRepository;
 
+    @Transactional
     public void createLetter(CreateLetterRequest request) {
         Mailbox findMailbox = mailboxRepository.getFirstByRegion(request.region());
         findMailbox.increaseLetterCount();
 
         Letter letter = Letter.of(request.content(), findMailbox, request.imageUrl());
         letterRepository.save(letter);
-        mailboxRepository.save(findMailbox);
     }
 
     public GetLettersResponse getLetters(String region){
         Mailbox findMailbox = mailboxRepository.getFirstByRegion(Region.fromKoreanName(region));
 
-        List<Letter> letters = letterRepository.findByMailbox(findMailbox);
+        List<Letter> letters = letterRepository.findByMailboxAndStatus(findMailbox, Status.ACTIVE);
 
         List<SimpleLetterDto> letterDtos = letters.stream()
                 .map(letter -> new SimpleLetterDto(
@@ -63,6 +66,7 @@ public GetLetterResponse getLetter(Long letterId){
         );
     }
 
+    @Transactional
     public void createStorage(Long userId, CreateStorageRequest request){
         User findUser = userRepository.getById(userId);
         Letter findLetter = letterRepository.getById(request.letterId());
@@ -86,4 +90,10 @@ public List<SimpleLetterDto> getStorages(Long userId){
                 })
                 .toList();
     }
+
+    @Transactional
+    public void reportLetter(Long letterId){
+        Letter findLetter = letterRepository.getById(letterId);
+        findLetter.report();
+    }
 }
diff --git a/src/main/java/com/cake/pop/entity/Letter.java b/src/main/java/com/cake/pop/entity/Letter.java
index a1c9dec..8fb505a 100644
--- a/src/main/java/com/cake/pop/entity/Letter.java
+++ b/src/main/java/com/cake/pop/entity/Letter.java
@@ -62,4 +62,11 @@ public static Letter of(String content, Mailbox mailbox, String imageUrl) {
                 .imageUrl(imageUrl)
                 .build();
     }
+
+    public void report() {
+        this.report++;
+        if (this.report >= 3) {
+            this.status = Status.INACTIVE;
+        }
+    }
 }