diff --git a/front/client/components/AddCategoryDialog.vue b/front/client/components/AddCategoryDialog.vue
index e93f3f0..f981148 100644
--- a/front/client/components/AddCategoryDialog.vue
+++ b/front/client/components/AddCategoryDialog.vue
@@ -1,58 +1,76 @@
 <template>
-  <v-dialog
-    :value="value"
-    @input="close"
-    max-width="500px"
-  >
+  <div>
+    <v-dialog
+      :value="value"
+      @input="close"
+      max-width="500px"
+    >
 
-    <slot slot="activator" />
+      <slot slot="activator" />
 
-    <v-card @keyup.esc.native="close" tabindex="0">
-      <v-card-text>
-        <v-form
-          ref="form"
-          lazy-validation
-          v-model="isValid"
-          @keydown.native.enter="submit"
-        >
-        <!-- v-if="value" - cause without it autofocus triggers on first modal open
-          https://stackoverflow.com/questions/51472947/vuetifys-autofocus-works-only-on-first-modal-open -->
-          <v-text-field
-            v-if="value"
-            class="mb-3"
-            label="Category name"
-            autofocus
-            :rules="categoryValidationRules"
-            v-model="categoryName"
-            ref="categoryNameInput"
-          />
-          <v-text-field
-            v-model="groupNameInternal"
-            label="Group"
-          />
-        </v-form>
-      </v-card-text>
-      <v-card-actions>
-        <v-spacer></v-spacer>
-        <v-btn
-          flat
-          color="primary"
-          @click.native="close"
-        >
-          Cancel
-        </v-btn>
-        <v-btn
-          flat
-          color="primary"
-          class="add-category-submit-btn"
-          :disabled="!isValid"
-          @click.native="submit"
-        >
-          Submit
-        </v-btn>
-      </v-card-actions>
-    </v-card>
-  </v-dialog>
+      <v-card @keyup.esc.native="close" tabindex="0">
+        <v-card-text>
+          <v-form
+            ref="form"
+            lazy-validation
+            v-model="isValid"
+            @keydown.native.enter="submit"
+          >
+          <!-- v-if="value" - cause without it autofocus triggers on first modal open
+            https://stackoverflow.com/questions/51472947/vuetifys-autofocus-works-only-on-first-modal-open -->
+            <v-text-field
+              v-if="value"
+              class="mb-3"
+              label="Category name"
+              autofocus
+              :rules="categoryValidationRules"
+              v-model="categoryName"
+              ref="categoryNameInput"
+            />
+            <v-text-field
+              v-model="groupNameInternal"
+              label="Group"
+            />
+          </v-form>
+        </v-card-text>
+        <v-card-actions>
+          <v-spacer></v-spacer>
+          <v-btn
+            flat
+            color="primary"
+            @click.native="close"
+          >
+            Cancel
+          </v-btn>
+          <v-btn
+            flat
+            color="primary"
+            class="add-category-submit-btn"
+            :disabled="!isValid"
+            @click.native="submit"
+          >
+            Submit
+          </v-btn>
+        </v-card-actions>
+      </v-card>
+
+    </v-dialog>
+
+    <ConfirmDialog
+      v-if="isDuplicateConfirmShow"
+      :value="isDuplicateConfirmShow"
+      max-width="500px"
+      attach="#app"
+      ref="duplicateConfirm"
+    >
+      This group already has categories with the same name:
+      <a
+        v-for="category in sameNameCategories"
+        :key="category.id"
+        target="_blank"
+      >{{ category.title }}</a>
+    </ConfirmDialog>
+  </div>
 </template>
 
 <script lang="ts">
@@ -60,18 +78,37 @@ import Vue from 'vue'
 import Component from 'vue-class-component'
 import { Prop, Watch } from 'vue-property-decorator'
 import { CategoryService } from 'client/service/Category'
+import ConfirmDialog from 'client/components/ConfirmDialog.vue'
+import DeferredPromise from 'utils/DeferredPromise'
 
-@Component
+@Component({
+  components: {
+    ConfirmDialog
+  }
+})
 export default class AddCategoryDialog extends Vue {
   @Prop(String) groupName!: string
   @Prop(Boolean) value!: boolean
 
   groupNameInternal: string = this.groupName || ''
   categoryName: string = ''
-  categoryValidationRules: Function[] = [
+  categoryValidationRules: Array<(x: string) => boolean | string> = [
     (x: string) => !!x || `Category name can't be empty`
   ]
   isValid: boolean = false
+  isDuplicateConfirmShow: boolean = false
+
+  get categories () {
+    return this.$store.state.category.categoryList
+  }
+
+  get sameNameCategories () {
+    if (!this.categoryName || !this.groupName) {
+      return []
+    }
+    return this.categories
+      .filter(x => x.group === this.groupName && x.title === this.categoryName)
+  }
 
   @Watch('value')
   onOpen (newVal: boolean) {
@@ -87,12 +124,37 @@ export default class AddCategoryDialog extends Vue {
     if (!this.$refs.form.validate()) {
       return
     }
+
+    if (this.sameNameCategories.length) {
+      const isDuplicationConfirmed = await this.confirmDuplicate()
+      if (!isDuplicationConfirmed) {
+        return
+      }
+    }
+
     const createdId = await this.$store.dispatch('category/createCategory', {
       title: this.categoryName,
       group: this.groupNameInternal
     })
     this.$router.push(`haskell/${createdId}`)
   }
+
+  async confirmDuplicate () {
+    const promise = new DeferredPromise()
+    this.isDuplicateConfirmShow = true
+    this.$nextTick(() => {
+      const duplicateConfirm = this.$refs.duplicateConfirm
+      duplicateConfirm.$once('canceled', () => {
+        promise.resolve(false)
+        this.isDuplicateConfirmShow = false
+      })
+      duplicateConfirm.$once('confirmed', () => {
+        promise.resolve(true)
+        this.isDuplicateConfirmShow = false
+      })
+    })
+    return promise
+  }
 }
 </script>
 
diff --git a/front/client/components/ConfirmDialog.vue b/front/client/components/ConfirmDialog.vue
index 66d4917..c2deee8 100644
--- a/front/client/components/ConfirmDialog.vue
+++ b/front/client/components/ConfirmDialog.vue
@@ -2,14 +2,18 @@
 <template>
   <v-dialog
     :value="value"
-    @input="close"
+    :attach="attach"
     max-width="500px"
+    @input="close"
   >
     <slot slot="activator" />
 
     <v-card>
-      <v-card-text>
-        Are you sure you want to {{ text }} ?
+      <v-card-text v-if="$slots.default">
+        <slot />
+      </v-card-text>
+      <v-card-text v-else>
+        {{ fullText || `Are you sure you want to ${text} ?` }}
       </v-card-text>
       <v-divider />
       <v-card-actions>
@@ -17,17 +21,16 @@
         <v-btn
           flat
           color="primary"
-          class="confirm-btn"
-          @click.native="confirm"
+          @click.native="cancel"
         >
-          {{ confirmBtnText }}
+          {{ cancelBtnText }}
         </v-btn>
         <v-btn
           flat
           color="primary"
-          @click.native="cancel"
+          @click.native="confirm"
         >
-          {{ cancelBtnText }}
+          {{ confirmBtnText }}
         </v-btn>
       </v-card-actions>
     </v-card>
@@ -42,12 +45,15 @@ import { Prop } from 'vue-property-decorator'
 @Component
 export default class ConfirmDialog extends Vue {
   @Prop(String) text!: string
+  @Prop(String) fullText!: string
   @Prop(Boolean) value!: boolean
+  @Prop(String) attach!: string
   @Prop({ default: 'Continue' }) confirmBtnText!: string
   @Prop({ default: 'Cancel' }) cancelBtnText!: string
 
   close () {
     this.$emit('input', false)
+    this.$emit('canceled')
   }
   confirm () {
     this.$emit('confirmed')
diff --git a/front/client/helpers/ConfirmDecorator.ts b/front/client/helpers/ConfirmDecorator.ts
index 268bf03..1958802 100644
--- a/front/client/helpers/ConfirmDecorator.ts
+++ b/front/client/helpers/ConfirmDecorator.ts
@@ -1,14 +1,17 @@
 interface IConfirmDialogProps {
-  text: string,
-  confirmBtnText?: string,
+  fullText: string
+  text: string
+  confirmBtnText?: string
   cancelBtnText?: string
 }
+// TODO looks like documentation isn't working
 /**
  * Use only for vue components methods.
  * Executes '_confirm' function (see confirmDialogMixin.ts) with provided options before executing following method.
  * If not confirmed method is not executed.
  * @param {Object} options - options passed to _confirm function
  * @param {String} options.text
+ * @param {String} options.fullText
  * @param {String} options.confirmBtnText
  * @param {String} options.cancelBtnText
  */
diff --git a/front/client/mixins/confirmDialogMixin.ts b/front/client/mixins/confirmDialogMixin.ts
index 9128905..12a8159 100644
--- a/front/client/mixins/confirmDialogMixin.ts
+++ b/front/client/mixins/confirmDialogMixin.ts
@@ -6,18 +6,20 @@ import DeferredPromise from 'utils/DeferredPromise'
 const ComponentClass = Vue.extend(ConfirmDialog)
 
 interface IConfirmDialogProps {
-  text: string,
-  confirmBtnText?: string,
+  fullText: string
+  text: string
+  confirmBtnText?: string
   cancelBtnText?: string
 }
 
 @Mixin
 export default class ConfirmDialogMixin extends Vue {
-  async _confirm ({ text, confirmBtnText, cancelBtnText }: IConfirmDialogProps): Promise<boolean> {
+  async _confirm ({ text, fullText, confirmBtnText, cancelBtnText }: IConfirmDialogProps): Promise<boolean> {
     const instance = new ComponentClass({
       propsData: {
         value: true,
         text,
+        fullText,
         confirmBtnText,
         cancelBtnText
       }