diff --git a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/exception/RestException.kt b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/exception/RestException.kt
index 1bc62b7..7e64182 100644
--- a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/exception/RestException.kt
+++ b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/exception/RestException.kt
@@ -59,6 +59,17 @@ class AlreadyExistsException(
     extensions = extensions.apply { this[identifierName] = identifierValue }.toMap()
 )
 
+class CannotUpdateException(
+    errorCode: String,
+    title: String,
+    details: String
+) : RestException(
+    errorCode = "cannotupdate-$errorCode",
+    title = title,
+    status = HttpStatus.BAD_REQUEST,
+    details = details
+)
+
 class CannotDeleteException(
     errorCode: String,
     title: String,
diff --git a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/model/MaterialType.kt b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/model/MaterialType.kt
index d19ac34..7abc3b7 100644
--- a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/model/MaterialType.kt
+++ b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/model/MaterialType.kt
@@ -2,6 +2,7 @@ package dev.fyloz.colorrecipesexplorer.model
 
 import dev.fyloz.colorrecipesexplorer.exception.AlreadyExistsException
 import dev.fyloz.colorrecipesexplorer.exception.CannotDeleteException
+import dev.fyloz.colorrecipesexplorer.exception.CannotUpdateException
 import dev.fyloz.colorrecipesexplorer.exception.NotFoundException
 import dev.fyloz.colorrecipesexplorer.model.validation.NullOrNotBlank
 import dev.fyloz.colorrecipesexplorer.model.validation.NullOrSize
@@ -105,6 +106,7 @@ fun materialTypeUpdateDto(
 private const val MATERIAL_TYPE_NOT_FOUND_EXCEPTION_TITLE = "Material type not found"
 private const val MATERIAL_TYPE_ALREADY_EXISTS_EXCEPTION_TITLE = "Material type already exists"
 private const val MATERIAL_TYPE_CANNOT_DELETE_EXCEPTION_TITLE = "Cannot delete material type"
+private const val MATERIAL_TYPE_CANNOT_UPDATE_EXCEPTION_TITLE = "Cannot update material type"
 private const val MATERIAL_TYPE_EXCEPTION_ERROR_CODE = "materialtype"
 
 fun materialTypeIdNotFoundException(id: Long) =
@@ -150,9 +152,23 @@ fun materialTypePrefixAlreadyExistsException(prefix: String) =
     "prefix"
   )
 
+fun cannotUpdateSystemMaterialTypeException(materialType: MaterialType) =
+  CannotUpdateException(
+    MATERIAL_TYPE_EXCEPTION_ERROR_CODE,
+    MATERIAL_TYPE_CANNOT_UPDATE_EXCEPTION_TITLE,
+    "Cannot update material type ${materialType.name} because it is a system material type"
+  )
+
 fun cannotDeleteMaterialTypeException(materialType: MaterialType) =
   CannotDeleteException(
     MATERIAL_TYPE_EXCEPTION_ERROR_CODE,
     MATERIAL_TYPE_CANNOT_DELETE_EXCEPTION_TITLE,
     "Cannot delete material type ${materialType.name} because one or more materials depends on it"
   )
+
+fun cannotDeleteSystemMaterialTypeException(materialType: MaterialType) =
+  CannotDeleteException(
+    MATERIAL_TYPE_EXCEPTION_ERROR_CODE,
+    MATERIAL_TYPE_CANNOT_DELETE_EXCEPTION_TITLE,
+    "Cannot delete material type ${materialType.name} because it is a system material type"
+  )
diff --git a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/repository/MaterialTypeRepository.kt b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/repository/MaterialTypeRepository.kt
index a664876..d90b51e 100644
--- a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/repository/MaterialTypeRepository.kt
+++ b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/repository/MaterialTypeRepository.kt
@@ -9,6 +9,9 @@ interface MaterialTypeRepository : NamedJpaRepository<MaterialType> {
     /** Checks if a material type exists with the given [prefix]. */
     fun existsByPrefix(prefix: String): Boolean
 
+    /** Checks if a system material type with the given [id] exists. */
+    fun existsByIdAndSystemTypeIsTrue(id: Long): Boolean
+
     /** Gets all material types which are not system types. */
     fun findAllBySystemTypeIs(value: Boolean): Collection<MaterialType>
 
diff --git a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeService.kt b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeService.kt
index 8d0ce96..0b37703 100644
--- a/src/main/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeService.kt
+++ b/src/main/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeService.kt
@@ -66,16 +66,24 @@ class MaterialTypeServiceImpl(repository: MaterialTypeRepository, private val ma
     }
 
     override fun update(entity: MaterialType): MaterialType {
+        if (repository.existsByIdAndSystemTypeIsTrue(entity.id!!)) {
+            throw cannotUpdateSystemMaterialTypeException(entity)
+        }
+
         with(repository.findByPrefix(entity.prefix)) {
             if (this != null && id != entity.id)
                 throw materialTypePrefixAlreadyExistsException(entity.prefix)
         }
 
-        return super<AbstractExternalNamedModelService>.update(entity)
+        return super.update(entity)
     }
 
     override fun delete(entity: MaterialType) {
-        if (!repository.canBeDeleted(entity.id!!)) throw cannotDeleteMaterialTypeException(entity)
+        if (repository.existsByIdAndSystemTypeIsTrue(entity.id!!)) {
+            throw cannotDeleteSystemMaterialTypeException(entity)
+        }
+
+        if (!repository.canBeDeleted(entity.id)) throw cannotDeleteMaterialTypeException(entity)
         super.delete(entity)
     }
 
diff --git a/src/test/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeServiceTest.kt b/src/test/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeServiceTest.kt
index 7d8a1dd..ea0a5f4 100644
--- a/src/test/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeServiceTest.kt
+++ b/src/test/kotlin/dev/fyloz/colorrecipesexplorer/service/MaterialTypeServiceTest.kt
@@ -2,6 +2,8 @@ package dev.fyloz.colorrecipesexplorer.service
 
 import com.nhaarman.mockitokotlin2.*
 import dev.fyloz.colorrecipesexplorer.exception.AlreadyExistsException
+import dev.fyloz.colorrecipesexplorer.exception.CannotDeleteException
+import dev.fyloz.colorrecipesexplorer.exception.CannotUpdateException
 import dev.fyloz.colorrecipesexplorer.exception.NotFoundException
 import dev.fyloz.colorrecipesexplorer.model.*
 import dev.fyloz.colorrecipesexplorer.repository.MaterialTypeRepository
@@ -164,8 +166,22 @@ class MaterialTypeServiceTest :
           .assertErrorCode("prefix")
     }
 
+    @Test
+    fun `update() throws CannotUpdateException when updating a system material type`() {
+        whenever(repository.existsByIdAndSystemTypeIsTrue(systemType.id!!)).doReturn(true)
+
+        assertThrows<CannotUpdateException> { service.update(systemType) }
+    }
+
     // delete()
 
+    @Test
+    fun `delete() throws CannotDeleteException when deleting a system material type`() {
+        whenever(repository.existsByIdAndSystemTypeIsTrue(systemType.id!!)).doReturn(true)
+
+        assertThrows<CannotDeleteException> { service.delete(systemType) }
+    }
+
     override fun `delete() deletes in the repository`() {
         whenCanBeDeleted {
             super.`delete() deletes in the repository`()