diff --git a/backend/app/src/test/kotlin/io/tolgee/api/v2/controllers/v2ImportController/V2ImportControllerAddFilesTest.kt b/backend/app/src/test/kotlin/io/tolgee/api/v2/controllers/v2ImportController/V2ImportControllerAddFilesTest.kt
index c60bfe83fd..856d60c8d5 100644
--- a/backend/app/src/test/kotlin/io/tolgee/api/v2/controllers/v2ImportController/V2ImportControllerAddFilesTest.kt
+++ b/backend/app/src/test/kotlin/io/tolgee/api/v2/controllers/v2ImportController/V2ImportControllerAddFilesTest.kt
@@ -348,6 +348,23 @@ class V2ImportControllerAddFilesTest : ProjectAuthControllerTest("/v2/projects/"
     }
   }
 
+  @Test
+  fun `import gets deleted after namespaces feature is toggled`() {
+    val base = dbPopulator.createBase()
+
+    performImport(projectId = base.project.id, listOf("simple.json" to simpleJson))
+      .andIsOk
+
+    assertThat(importService.getAllByProject(base.project.id)).isNotEmpty()
+
+    val project = projectService.get(base.project.id)
+    project.useNamespaces = !project.useNamespaces
+    projectService.save(project)
+    commitTransaction()
+
+    assertThat(importService.getAllByProject(project.id)).isEmpty()
+  }
+
   private fun validateSavedJsonImportData(
     project: Project,
     userAccount: UserAccount,
diff --git a/backend/data/src/main/kotlin/io/tolgee/model/Project.kt b/backend/data/src/main/kotlin/io/tolgee/model/Project.kt
index 63938bfc71..abf7c25a32 100644
--- a/backend/data/src/main/kotlin/io/tolgee/model/Project.kt
+++ b/backend/data/src/main/kotlin/io/tolgee/model/Project.kt
@@ -126,6 +126,7 @@ class Project(
   override var icuPlaceholders: Boolean = true
 
   @ColumnDefault("false")
+  @ActivityLoggedProp
   var useNamespaces: Boolean = false
 
   @ColumnDefault("0")
diff --git a/backend/data/src/main/kotlin/io/tolgee/service/dataImport/ImportService.kt b/backend/data/src/main/kotlin/io/tolgee/service/dataImport/ImportService.kt
index 0d456bbc9b..59069ef5f2 100644
--- a/backend/data/src/main/kotlin/io/tolgee/service/dataImport/ImportService.kt
+++ b/backend/data/src/main/kotlin/io/tolgee/service/dataImport/ImportService.kt
@@ -12,6 +12,7 @@ import io.tolgee.dtos.dataImport.ImportAddFilesParams
 import io.tolgee.dtos.dataImport.ImportFileDto
 import io.tolgee.dtos.request.SingleStepImportRequest
 import io.tolgee.events.OnImportSoftDeleted
+import io.tolgee.events.OnProjectActivityEvent
 import io.tolgee.exceptions.BadRequestException
 import io.tolgee.exceptions.ErrorResponseBody
 import io.tolgee.exceptions.ImportConflictNotResolvedException
@@ -19,21 +20,13 @@ import io.tolgee.exceptions.NotFoundException
 import io.tolgee.model.Language
 import io.tolgee.model.Project
 import io.tolgee.model.UserAccount
-import io.tolgee.model.dataImport.Import
-import io.tolgee.model.dataImport.ImportFile
-import io.tolgee.model.dataImport.ImportKey
-import io.tolgee.model.dataImport.ImportLanguage
-import io.tolgee.model.dataImport.ImportTranslation
+import io.tolgee.model.dataImport.*
 import io.tolgee.model.dataImport.issues.ImportFileIssue
 import io.tolgee.model.dataImport.issues.ImportFileIssueParam
 import io.tolgee.model.views.ImportFileIssueView
 import io.tolgee.model.views.ImportLanguageView
 import io.tolgee.model.views.ImportTranslationView
-import io.tolgee.repository.dataImport.ImportFileRepository
-import io.tolgee.repository.dataImport.ImportKeyRepository
-import io.tolgee.repository.dataImport.ImportLanguageRepository
-import io.tolgee.repository.dataImport.ImportRepository
-import io.tolgee.repository.dataImport.ImportTranslationRepository
+import io.tolgee.repository.dataImport.*
 import io.tolgee.repository.dataImport.issues.ImportFileIssueParamRepository
 import io.tolgee.repository.dataImport.issues.ImportFileIssueRepository
 import io.tolgee.service.dataImport.status.ImportApplicationStatus
@@ -41,6 +34,7 @@ import io.tolgee.util.getSafeNamespace
 import jakarta.persistence.EntityManager
 import org.springframework.context.ApplicationContext
 import org.springframework.context.annotation.Lazy
+import org.springframework.context.event.EventListener
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 import org.springframework.jdbc.core.JdbcTemplate
@@ -413,6 +407,20 @@ class ImportService(
     dataManager.resetCollisionsBetweenFiles(language, null)
   }
 
+  @EventListener
+  fun deleteExistingImportsOnUseNamespacesModification(event: OnProjectActivityEvent) {
+    val modifiedProjects = event.modifiedEntities[Project::class]
+
+    modifiedProjects
+      ?.values
+      ?.filter { project -> project.modifications.containsKey("useNamespaces") }
+      ?.forEach { project ->
+        getAllByProject(project.entityId).forEach { import ->
+          deleteImport(import)
+        }
+      }
+  }
+
   fun findTranslation(translationId: Long): ImportTranslation? {
     return importTranslationRepository.findById(translationId).orElse(null)
   }