diff --git a/src/components/card/CardSidebarTabComments.vue b/src/components/card/CardSidebarTabComments.vue
index a4c403625..4235e2c61 100644
--- a/src/components/card/CardSidebarTabComments.vue
+++ b/src/components/card/CardSidebarTabComments.vue
@@ -88,6 +88,9 @@ export default {
 			this.isLoading = true
 			await this.$store.dispatch('fetchComments', { cardId: this.card.id })
 			this.isLoading = false
+			if (this.card.commentsUnread > 0) {
+				await this.$store.dispatch('markCommentsAsRead', this.card.id)
+			}
 		},
 		async createComment(content) {
 			const commentObj = {
diff --git a/src/components/cards/CardBadges.vue b/src/components/cards/CardBadges.vue
index a816ce81f..4f5abe70c 100644
--- a/src/components/cards/CardBadges.vue
+++ b/src/components/cards/CardBadges.vue
@@ -22,7 +22,10 @@
 
 <template>
 	<div class="badges">
-		<div v-if="card.description" class="card-comments icon icon-edit" />
+		<div v-if="card.description" class="icon icon-edit" />
+
+		<div v-if="card.commentsUnread > 0" class="icon icon-comment" />
+
 
 		<div v-if="card.duedate" :class="dueIcon">
 			<span>{{ dueTime }}</span>
diff --git a/src/helpers/xml.js b/src/helpers/xml.js
index 83e8ba376..4c151b62d 100644
--- a/src/helpers/xml.js
+++ b/src/helpers/xml.js
@@ -52,6 +52,7 @@ const commentToObject = (tag) => {
 		actorDisplayName: tag['d:prop']['oc:actorDisplayName']['#text'],
 		creationDateTime: tag['d:prop']['oc:creationDateTime']['#text'],
 		message: tag['d:prop']['oc:message']['#text'],
+		isUnread: tag['d:prop']['oc:isUnread']['#text'] === 'true',
 		mentions: mentions.map((mention) => {
 			return {
 				mentionType: mention['oc:mentionType']['#text'],
diff --git a/src/services/CommentApi.js b/src/services/CommentApi.js
index 6cc3d4d01..d47f2ea5a 100644
--- a/src/services/CommentApi.js
+++ b/src/services/CommentApi.js
@@ -112,4 +112,21 @@ export class CommentApi {
 		return response.data
 	}
 
+	async markCommentsAsRead(cardId) {
+		const readMarker = (new Date()).toUTCString()
+		const response = await axios({
+			method: 'PROPPATCH',
+			url: this.url(`${cardId}`),
+			data: `<?xml version="1.0"?>
+				<d:propertyupdate  xmlns:d="DAV:" xmlns:oc="http://owncloud.org/ns">
+				  <d:set>
+				   <d:prop>
+					  <oc:readMarker>${readMarker}</oc:readMarker>
+					</d:prop>
+				  </d:set>
+				</d:propertyupdate>`,
+		})
+		return response.data
+	}
+
 }
diff --git a/src/store/comment.js b/src/store/comment.js
index f3c5f448d..8b90c5978 100644
--- a/src/store/comment.js
+++ b/src/store/comment.js
@@ -68,11 +68,16 @@ export default {
 			}
 		},
 		deleteComment(state, comment) {
-			const existingIndex = state.comments[comment.cardId].comments.findIndex(_comment => _comment.id === comment.commentId)
+			const existingIndex = state.comments[comment.cardId].comments.findIndex(_comment => _comment.id === comment.id)
 			if (existingIndex !== -1) {
 				state.comments[comment.cardId].comments.splice(existingIndex, 1)
 			}
 		},
+		markCommentsAsRead(state, cardId) {
+			state.comments[cardId].comments.forEach(_comment => {
+				Vue.set(_comment, 'isUnread', false)
+			})
+		}
 	},
 	actions: {
 		async fetchComments({ commit }, { cardId, offset }) {
@@ -111,5 +116,9 @@ export default {
 			const commentData = await apiClient.fetchComment(data)
 			await commit('updateComment', { cardId: data.cardId, comment: commentData[0] })
 		},
+		async markCommentsAsRead({ commit }, cardId) {
+			await apiClient.markCommentsAsRead(cardId)
+			await commit('markCommentsAsRead', cardId)
+		}
 	},
 }