diff --git a/README.md b/README.md
index 670a2e23..946847e0 100644
--- a/README.md
+++ b/README.md
@@ -61,4 +61,5 @@ type Locator struct {
 - `GET /api/v1/id/{id}` - get comment by `id`
 - `GET /api/v1/count?url=post-url` - get comment's count for `{url}`
 - `PUT /api/v1/vote/{id}?url=post-url&vote=1` - vote for comment. `vote`=1 will increase score, -1 decreases. _auth required_
-- `DELETE /api/v1/comment/{id}?url=post-url` - delete comment by `id`. _auth and admin required_
\ No newline at end of file
+- `DELETE /api/v1/comment/{id}?url=post-url` - delete comment by `id`. _auth and admin required_
+- `PUT /user/{userid}?site=side-id&block=1` - block or unblock user. _auth and admin required_
diff --git a/app/rest/moderator.go b/app/rest/moderator.go
index b6462be5..5578567d 100644
--- a/app/rest/moderator.go
+++ b/app/rest/moderator.go
@@ -18,6 +18,7 @@ func (m *moderator) routes() chi.Router {
 	router := chi.NewRouter()
 	router.Use(AdminOnly)
 	router.Delete("/comment/{id}", m.deleteCommentCtrl)
+	router.Put("/user/{userid}", m.setBlockCtrl)
 	return router
 }
 
@@ -28,6 +29,7 @@ func (m *moderator) deleteCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		log.Printf("[WARN] bad id %s", chi.URLParam(r, "id"))
 		httpError(w, r, http.StatusBadRequest, err, "can't parse id")
+		return
 	}
 
 	log.Printf("[INFO] delete comment %d", id)
@@ -43,3 +45,17 @@ func (m *moderator) deleteCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	render.Status(r, http.StatusOK)
 	render.JSON(w, r, JSON{"id": id, "url": url})
 }
+
+// PUT /user/{userid}?site=side-id&block=1
+func (m *moderator) setBlockCtrl(w http.ResponseWriter, r *http.Request) {
+	userID := chi.URLParam(r, "userid")
+	siteID := r.URL.Query().Get("site")
+	blockStatus := r.URL.Query().Get("block") == "1"
+
+	if err := m.dataStore.SetBlock(store.Locator{SiteID: siteID}, userID, blockStatus); err != nil {
+		httpError(w, r, http.StatusBadRequest, err, "can't set blocking status")
+		return
+	}
+
+	render.JSON(w, r, JSON{"user_id": userID, "site_id": siteID, "block": blockStatus})
+}
diff --git a/app/rest/server.go b/app/rest/server.go
index bf6c0707..bc165ed2 100644
--- a/app/rest/server.go
+++ b/app/rest/server.go
@@ -1,6 +1,7 @@
 package rest
 
 import (
+	"errors"
 	"html/template"
 	"log"
 	"net/http"
@@ -98,7 +99,7 @@ func (s *Server) createCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	}
 
 	user, err := GetUserInfo(r)
-	if err != nil {
+	if err != nil { // this not suppose to happen (handled by Auth), just dbl-check
 		httpError(w, r, http.StatusUnauthorized, err, "can't get user info")
 		return
 	}
@@ -114,6 +115,13 @@ func (s *Server) createCommentCtrl(w http.ResponseWriter, r *http.Request) {
 
 	log.Printf("[INFO] create comment %+v", comment)
 
+	// check if user blocked
+	if s.Store.IsBlocked(store.Locator{}, comment.User.ID) {
+		log.Printf("[WARN] user %s rejected (blocked)", err)
+		httpError(w, r, http.StatusForbidden, errors.New("rejected"), "user blocked")
+		return
+	}
+
 	id, err := s.Store.Create(comment)
 	if err != nil {
 		log.Printf("[WARN] can't save comment, %s", err)
diff --git a/app/store/bolt.go b/app/store/bolt.go
index 59c755bd..56a915d6 100644
--- a/app/store/bolt.go
+++ b/app/store/bolt.go
@@ -20,7 +20,10 @@ type BoltDB struct {
 	*bolt.DB
 }
 
-var lastBucketName = "last"
+var (
+	lastBucketName     = "last"
+	blocksBucketPrefix = "block-"
+)
 
 // NewBoltDB makes persistent boltdb-based store
 func NewBoltDB(dbFile string) (*BoltDB, error) {
@@ -270,6 +273,48 @@ func (b *BoltDB) Count(locator Locator) (count int, err error) {
 	return count, err
 }
 
+// SetBlock blocks/unblocks user for given site
+func (b *BoltDB) SetBlock(locator Locator, userID string, status bool) error {
+	blockBucketName := b.bucketForBlock(locator, userID)
+	return b.Update(func(tx *bolt.Tx) error {
+
+		bucket, e := tx.CreateBucketIfNotExists([]byte(blockBucketName))
+		if e != nil {
+			return errors.Errorf("no bucket %s in store", string(blockBucketName))
+		}
+
+		switch status {
+		case true:
+			if e := bucket.Put([]byte(userID), []byte(time.Now().Format(time.RFC3339))); e != nil {
+				return errors.Wrapf(e, "failed to put %s to %s", userID, string(blockBucketName))
+			}
+		case false:
+			if e := bucket.Delete([]byte(userID)); e != nil {
+				return errors.Wrapf(e, "failed to clean %s from %s", userID, string(blockBucketName))
+			}
+		}
+		return nil
+	})
+}
+
+// IsBlocked checks if user blocked
+func (b *BoltDB) IsBlocked(locator Locator, userID string) (result bool) {
+	blockBucketName := b.bucketForBlock(locator, userID)
+	_ = b.View(func(tx *bolt.Tx) error {
+		result = false
+		bucket := tx.Bucket(blockBucketName)
+		if bucket != nil && bucket.Get([]byte(userID)) != nil {
+			result = true
+		}
+		return nil
+	})
+	return result
+}
+
+func (b *BoltDB) bucketForBlock(locator Locator, userID string) []byte {
+	return []byte(fmt.Sprintf("%s%s", blocksBucketPrefix, locator.SiteID))
+}
+
 func (b *BoltDB) keyFromComment(comment Comment) []byte {
 	return []byte(fmt.Sprintf("%22d", comment.ID))
 }
diff --git a/app/store/bolt_test.go b/app/store/bolt_test.go
index a0a0666e..f24640e3 100644
--- a/app/store/bolt_test.go
+++ b/app/store/bolt_test.go
@@ -27,17 +27,22 @@ func TestBoltDB_Delete(t *testing.T) {
 	defer os.Remove(testDb)
 	b := prep(t)
 
-	res, err := b.Find(Request{Locator: Locator{URL: "https://radio-t.com"}})
+	loc := Locator{URL: "https://radio-t.com"}
+	res, err := b.Find(Request{Locator: loc})
 	assert.Nil(t, err)
 	assert.Equal(t, 2, len(res))
 
-	err = b.Delete(Locator{URL: "https://radio-t.com"}, res[0].ID)
+	err = b.Delete(loc, res[0].ID)
 	assert.Nil(t, err)
 
-	res, err = b.Find(Request{Locator: Locator{URL: "https://radio-t.com"}})
+	res, err = b.Find(Request{Locator: loc})
 	assert.Nil(t, err)
 	assert.Equal(t, 1, len(res))
 	assert.Equal(t, "some text2", res[0].Text)
+
+	comments, err := b.Last(loc, 10)
+	assert.Nil(t, err)
+	assert.Equal(t, 1, len(comments), "only 1 left in last")
 }
 
 func TestBoltDB_Get(t *testing.T) {
@@ -105,6 +110,22 @@ func TestBoltDB_Count(t *testing.T) {
 	assert.Equal(t, 2, c)
 }
 
+func TestBoltDB_BlockUser(t *testing.T) {
+	defer os.Remove(testDb)
+	b := prep(t)
+
+	assert.False(t, b.IsBlocked(Locator{SiteID: "site1"}, "user1"), "nothing blocked")
+
+	assert.NoError(t, b.SetBlock(Locator{SiteID: "site1"}, "user1", true))
+	assert.True(t, b.IsBlocked(Locator{SiteID: "site1"}, "user1"), "user1 blocked")
+
+	assert.False(t, b.IsBlocked(Locator{SiteID: "site1"}, "user2"), "user2 still unblocked")
+
+	assert.NoError(t, b.SetBlock(Locator{SiteID: "site1"}, "user1", false))
+	assert.False(t, b.IsBlocked(Locator{SiteID: "site1"}, "user1"), "user1 unblocked")
+
+}
+
 // makes new boltdb, put two records
 func prep(t *testing.T) *BoltDB {
 	os.Remove(testDb)
diff --git a/app/store/store.go b/app/store/store.go
index afd451da..7e88d6d7 100644
--- a/app/store/store.go
+++ b/app/store/store.go
@@ -47,4 +47,7 @@ type Interface interface {
 	Get(locator Locator, id int64) (Comment, error)
 	Vote(locator Locator, commentID int64, userID string, val bool) (Comment, error)
 	Count(locator Locator) (int, error)
+
+	SetBlock(locator Locator, userID string, status bool) error
+	IsBlocked(locator Locator, userID string) bool
 }